diff --git a/auxil/gen-zam b/auxil/gen-zam
index 37d9fba879..4f9f5408d2 160000
--- a/auxil/gen-zam
+++ b/auxil/gen-zam
@@ -1 +1 @@
-Subproject commit 37d9fba879d191a9139528cbe441fa53db250e24
+Subproject commit 4f9f5408d2ea070a0295de25c1548e982a20baf1
diff --git a/src/script_opt/ZAM/OPs/ZAM.op b/src/script_opt/ZAM/OPs/ZAM.op
index c81fc216c6..37e008103b 100644
--- a/src/script_opt/ZAM/OPs/ZAM.op
+++ b/src/script_opt/ZAM/OPs/ZAM.op
@@ -262,7 +262,7 @@
 macro Z_TYPE z.t
 
 # Whether it's managed.
-macro Z_IS_MANAGED z.is_managed
+macro Z_IS_MANAGED *(z.is_managed)
 
 # Secondary type.
 macro Z_TYPE2 z.t2
diff --git a/src/script_opt/ZAM/ZInst.h b/src/script_opt/ZAM/ZInst.h
index 4f79e04da4..4c62523e85 100644
--- a/src/script_opt/ZAM/ZInst.h
+++ b/src/script_opt/ZAM/ZInst.h
@@ -140,7 +140,7 @@ public:
 
     // Whether v1 represents a frame slot type for which we
     // explicitly manage the memory.
-    bool is_managed = false;
+    std::optional<bool> is_managed;
 };
 
 // A intermediary ZAM instruction, one that includes information/methods