diff --git a/chain/stmgr/forks.go b/chain/stmgr/forks.go
index b6c6985e2..4fca13f96 100644
--- a/chain/stmgr/forks.go
+++ b/chain/stmgr/forks.go
@@ -211,11 +211,9 @@ func (sm *StateManager) handleStateForks(ctx context.Context, root cid.Cid, heig
 	return retCid, nil
 }
 
-// Returns true if executing the current tipset would trigger an expensive fork.
-//
-// - If the tipset is the genesis, this function always returns false.
-// - If inclusive is true, this function will also return true if applying a message on-top-of the
-//   tipset would trigger a fork.
+// Returns true executing tipsets between the specified heights would trigger an expensive
+// migration. NOTE: migrations occuring _at_ the target height are not included, as they're executed
+// _after_ the target height.
 func (sm *StateManager) hasExpensiveForkBetween(parent, height abi.ChainEpoch) bool {
 	for h := parent; h < height; h++ {
 		if _, ok := sm.expensiveUpgrades[h]; ok {
diff --git a/chain/stmgr/forks_test.go b/chain/stmgr/forks_test.go
index 97ec8643b..6c507a0c4 100644
--- a/chain/stmgr/forks_test.go
+++ b/chain/stmgr/forks_test.go
@@ -310,7 +310,7 @@ func testForkRefuseCall(t *testing.T, nullsBefore, nullsAfter int) {
 	nullStart := abi.ChainEpoch(testForkHeight - nullsBefore)
 	nullLength := abi.ChainEpoch(nullsBefore + nullsAfter)
 
-	for i := 0; i < 50; i++ {
+	for i := 0; i < testForkHeight*2; i++ {
 		pts := cg.CurTipset.TipSet()
 		skip := abi.ChainEpoch(0)
 		if pts.Height() == nullStart {