diff --git a/ets2panda/ast_verifier/ASTVerifier.h b/ets2panda/ast_verifier/ASTVerifier.h
index f0d6315741c0a96d2810c77e19b6122506c8ff81..c215aa2db16573bd3bfd469d9a82fff54e448789 100644
--- a/ets2panda/ast_verifier/ASTVerifier.h
+++ b/ets2panda/ast_verifier/ASTVerifier.h
@@ -129,7 +129,8 @@ public:
                  i <= VerifierInvariants::AFTER_CHECKER_PHASE_LAST; i++) {
                 allowed_[i] = true;
             }
-            // NOTE(dkofanov): This should be called after "NumberLowering" phase:
+        }
+        if (occurredPhaseName == "Unbox") {
             Get<NoPrimitiveTypes>()->SetNumberLoweringOccured();
         }
         if (occurredPhaseName == "UnionLowering") {
diff --git a/ets2panda/ast_verifier/invariants/nodeHasType.h b/ets2panda/ast_verifier/invariants/nodeHasType.h
index 81769166cf67988b5c87153d932072722614aca2..edfee888c364fe11509d90b4cef6b0b0fe282e0d 100644
--- a/ets2panda/ast_verifier/invariants/nodeHasType.h
+++ b/ets2panda/ast_verifier/invariants/nodeHasType.h
@@ -49,7 +49,8 @@ public:
         if (type == nullptr) {
             return {CheckDecision::CORRECT, CheckAction::CONTINUE};
         }
-        if (!numberLoweringOccurred_ && type->IsETSPrimitiveType()) {
+        // NOTE(dkofanov): Broken extension functions.
+        if (!numberLoweringOccurred_ && !type->IsETSExtensionFuncHelperType() && type->IsETSPrimitiveType()) {
             AddCheckMessage("PRIMITIVE_BEFORE_LOWERING", *ast);
             return {CheckDecision::INCORRECT, CheckAction::CONTINUE};
         }