diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3f46e4be1..5987ee1c3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.36.29]
+
+### Fixed
+- **`/v1/health` reported a chain the node denies exists.** The `bootstrapped` check publishes `chains.Nets.Bootstrapping()` verbatim as its message, but `Nets.chains` is keyed by **net** ID and the aggregate appended the map **key**, not the chain. Every primary-network chain that failed to converge therefore surfaced as the single ID `11111111111111111111111111111111LpoYY` — `constants.PrimaryNetworkID` (`ids.Empty`) — so an operator resolving it got "there is no chain with alias/ID", and N stuck chains collapsed into one indistinguishable entry (measured on devnet/testnet: `"message":["11111111111111111111111111111111LpoYY"],"contiguousFailures":3213`). The net owns the bootstrapping set, so the net now names its own chains: new `nets.Net.Bootstrapping() []ids.ID` (`nets/net.go`), and `chains/chains.go` aggregates those instead of the keys. `TestNetsBootstrappingReportsChainsNotNets` asserts `ids.Empty` never appears and that two stuck chains are individually named; `TestNetsBootstrapping` no longer asserts the bug (it demanded the net ID).
+- Ships the GET `/v1/health` encoder fix from `dada5a31` (`{"healthy":…,"error":"health reply encode failed"}` on every node — jsonv2 has no representation for `apihealth.Result.Duration`), which was on `main` but had never been tagged.
+
 ## [1.36.13]
 
 ### Fixed
diff --git a/chains/chains.go b/chains/chains.go
index 4e45afe07..3917abd08 100644
--- a/chains/chains.go
+++ b/chains/chains.go
@@ -72,15 +72,22 @@ func (s *Nets) IsChainBootstrapped(chainID ids.ID) bool {
 
 // Bootstrapping returns the chainIDs of any chains that are still
 // bootstrapping.
+//
+// s.chains is keyed by NET id, not chain id. Reporting the key named the net
+// instead of the chain: every primary-network chain that failed to converge
+// surfaced in /v1/health as the single ID
+// "11111111111111111111111111111111LpoYY" — constants.PrimaryNetworkID, i.e.
+// ids.Empty — a "chain" the chain manager has never heard of, so the operator
+// chasing it got "there is no chain with alias/ID". Worse, N stuck chains
+// collapsed into one indistinguishable entry. Ask each net which of ITS chains
+// are still bootstrapping; the net owns that set.
 func (s *Nets) Bootstrapping() []ids.ID {
 	s.lock.RLock()
 	defer s.lock.RUnlock()
 
 	chainsBootstrapping := make([]ids.ID, 0, len(s.chains))
-	for chainID, chain := range s.chains {
-		if !chain.IsBootstrapped() {
-			chainsBootstrapping = append(chainsBootstrapping, chainID)
-		}
+	for _, chain := range s.chains {
+		chainsBootstrapping = append(chainsBootstrapping, chain.Bootstrapping()...)
 	}
 
 	return chainsBootstrapping
diff --git a/chains/chains_test.go b/chains/chains_test.go
index 58e743bab..93dbfc108 100644
--- a/chains/chains_test.go
+++ b/chains/chains_test.go
@@ -158,12 +158,54 @@ func TestNetsBootstrapping(t *testing.T) {
 	chain, ok := chains.GetOrCreate(netID)
 	require.True(ok)
 
-	// Start bootstrapping
+	// Start bootstrapping. What comes back is the CHAIN that is syncing, never
+	// the net that holds it — this assertion used to demand netID, which is
+	// how the phantom "11111111111111111111111111111111LpoYY" survived review.
 	chain.AddChain(chainID)
 	bootstrapping := chains.Bootstrapping()
-	require.Contains(bootstrapping, netID)
+	require.Equal([]ids.ID{chainID}, bootstrapping)
+	require.NotContains(bootstrapping, netID)
 
 	// Finish bootstrapping
 	chain.Bootstrapped(chainID)
 	require.Empty(chains.Bootstrapping())
 }
+
+// The "bootstrapped" health check publishes Nets.Bootstrapping() verbatim as
+// its message. s.chains is keyed by NET id, so returning the key reported
+// constants.PrimaryNetworkID (ids.Empty, cb58
+// "11111111111111111111111111111111LpoYY") as though it were an unbootstrapped
+// CHAIN. Operators saw a chain ID the chain manager denies exists, and every
+// stuck chain on the net collapsed into that one phantom entry.
+func TestNetsBootstrappingReportsChainsNotNets(t *testing.T) {
+	require := require.New(t)
+
+	chains, err := NewNets(ids.EmptyNodeID, map[ids.ID]nets.Config{
+		constants.PrimaryNetworkID: {},
+	})
+	require.NoError(err)
+
+	primary, _ := chains.GetOrCreate(constants.PrimaryNetworkID)
+	cChainID := ids.GenerateTestID()
+	dChainID := ids.GenerateTestID()
+	primary.AddChain(cChainID)
+	primary.AddChain(dChainID)
+
+	bootstrapping := chains.Bootstrapping()
+
+	// The phantom: never the net's own ID.
+	require.NotContains(bootstrapping, constants.PrimaryNetworkID)
+	require.NotContains(
+		bootstrapping,
+		ids.Empty,
+		"health check reported the primary NET id as an unbootstrapped chain",
+	)
+	// Both stuck chains must be individually nameable.
+	require.ElementsMatch([]ids.ID{cChainID, dChainID}, bootstrapping)
+
+	primary.Bootstrapped(cChainID)
+	require.Equal([]ids.ID{dChainID}, chains.Bootstrapping())
+
+	primary.Bootstrapped(dChainID)
+	require.Empty(chains.Bootstrapping())
+}
diff --git a/nets/net.go b/nets/net.go
index 1c03323ea..3f4f05ecf 100644
--- a/nets/net.go
+++ b/nets/net.go
@@ -34,6 +34,11 @@ type Net interface {
 	// IsBootstrapped returns true if the chains in this chain are done bootstrapping
 	IsBootstrapped() bool
 
+	// Bootstrapping returns the IDs of the chains in this net that have NOT yet
+	// finished initial sync. The net owns the bootstrapping set, so it is the
+	// net — not its caller — that can name those chains.
+	Bootstrapping() []ids.ID
+
 	// IsChainBootstrapped reports whether a SPECIFIC chain in this net has finished
 	// initial sync — i.e. Bootstrapped(chainID) was called for it (the chain reached
 	// the network frontier and its VM went to normal operation). This is the per-chain
@@ -75,6 +80,13 @@ func (s *chain) IsBootstrapped() bool {
 	return s.bootstrapping.Len() == 0
 }
 
+func (s *chain) Bootstrapping() []ids.ID {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.bootstrapping.List()
+}
+
 // IsChainBootstrapped assumes MONOTONIC per-process bootstrapped state: a chain
 // only ever moves bootstrapping→bootstrapped (Bootstrapped is forward-only and
 // AddChain refuses to re-add a chain already in either set), so this signal — and
diff --git a/nets/net_test.go b/nets/net_test.go
index 656dfe8fa..97a3b2698 100644
--- a/nets/net_test.go
+++ b/nets/net_test.go
@@ -68,3 +68,26 @@ func TestIsAllowed(t *testing.T) {
 	require.False(s.IsAllowed(ids.GenerateTestNodeID(), false), "Non-validator should not be allowed with validator only rules and allowed nodes")
 	require.True(s.IsAllowed(allowedNodeID, true), "Non-validator allowed node should be allowed with validator only rules and allowed nodes")
 }
+
+// Bootstrapping must name the CHAINS still syncing. The net-level aggregate
+// IsBootstrapped() only says "something here is unconverged"; only the chain
+// IDs say what.
+func TestNetBootstrappingNamesTheChains(t *testing.T) {
+	require := require.New(t)
+
+	chainID0 := ids.GenerateTestID()
+	chainID1 := ids.GenerateTestID()
+
+	s := New(ids.GenerateTestNodeID(), Config{})
+	require.Empty(s.Bootstrapping())
+
+	s.AddChain(chainID0)
+	s.AddChain(chainID1)
+	require.ElementsMatch([]ids.ID{chainID0, chainID1}, s.Bootstrapping())
+
+	s.Bootstrapped(chainID0)
+	require.Equal([]ids.ID{chainID1}, s.Bootstrapping())
+
+	s.Bootstrapped(chainID1)
+	require.Empty(s.Bootstrapping())
+}
diff --git a/version/constants.go b/version/constants.go
index 80036a13b..a2113fa83 100644
--- a/version/constants.go
+++ b/version/constants.go
@@ -77,7 +77,7 @@ var (
 const (
 	defaultMajor = 1
 	defaultMinor = 36
-	defaultPatch = 28
+	defaultPatch = 29
 )
 
 func init() {