diff --git a/.changelog/18558.txt b/.changelog/18558.txt
new file mode 100644
index 000000000..9c2b9b44b
--- /dev/null
+++ b/.changelog/18558.txt
@@ -0,0 +1,3 @@
+```release-note:bug
+check: prevent go routine leakage when existing Defercheck of same check id is not nil
+```
diff --git a/agent/local/state.go b/agent/local/state.go
index 3e43ddc9a..6cd5b0c82 100644
--- a/agent/local/state.go
+++ b/agent/local/state.go
@@ -838,6 +838,12 @@ func (l *State) setCheckStateLocked(c *CheckState) {
 	existing := l.checks[id]
 	if existing != nil {
 		c.InSync = c.Check.IsSame(existing.Check)
+		// If the existing check has a Defercheck, it needs to be
+		// assigned to the new check
+		if existing.DeferCheck != nil && c.DeferCheck == nil {
+			c.DeferCheck = existing.DeferCheck
+			c.InSync = false
+		}
 	}
 
 	l.checks[id] = c