diff --git a/src/common/proxy_wasm/ngx_proxy_wasm.c b/src/common/proxy_wasm/ngx_proxy_wasm.c
index bb5fd60d0..16aca5bd1 100644
--- a/src/common/proxy_wasm/ngx_proxy_wasm.c
+++ b/src/common/proxy_wasm/ngx_proxy_wasm.c
@@ -310,7 +310,9 @@ ngx_proxy_wasm_ctx_destroy(ngx_proxy_wasm_ctx_t *pwctx)
 
     dd("enter (pwctx: %p)", pwctx);
 
-    if (pwctx->isolation == NGX_PROXY_WASM_ISOLATION_STREAM && pwctx->ready) {
+    if (pwctx->ready
+        && pwctx->isolation == NGX_PROXY_WASM_ISOLATION_STREAM)
+    {
         ngx_proxy_wasm_store_destroy(&pwctx->store);
     }
 
@@ -336,9 +338,9 @@ ngx_proxy_wasm_ctx_destroy(ngx_proxy_wasm_ctx_t *pwctx)
             if (pwctx->isolation == NGX_PROXY_WASM_ISOLATION_NONE) {
                 /* sweep if an instance has trapped */
                 ngx_proxy_wasm_store_sweep(pwexec->ictx->store);
-            }
 
-            if (pwctx->isolation == NGX_PROXY_WASM_ISOLATION_FILTER) {
+            } else if (pwctx->isolation == NGX_PROXY_WASM_ISOLATION_FILTER) {
+                /* destroy filter context store */
                 ngx_proxy_wasm_store_destroy(pwexec->store);
             }
         }
@@ -1089,9 +1091,7 @@ ngx_proxy_wasm_create_context(ngx_proxy_wasm_filter_t *filter,
 
     if (id && (in == NULL || in->root_id != NGX_PROXY_WASM_ROOT_CTX_ID)) {
         pwexec = ngx_proxy_wasm_lookup_ctx(ictx, id);
-
-        dd("pwexec for id %ld: %p", id, pwexec);
-
+        dd("pwexec for id %ld: %p (in: %p)", id, pwexec, in);
         if (pwexec == NULL) {
 
             if (in == NULL) {
@@ -1664,7 +1664,7 @@ static void
 ngx_proxy_wasm_instance_invalidate(ngx_proxy_wasm_instance_t *ictx)
 {
     ngx_rbtree_node_t      **root, **sentinel, *s, *n;
-    ngx_proxy_wasm_exec_t   *pwexec = NULL;
+    ngx_proxy_wasm_exec_t   *pwexec;
 
     dd("enter (ictx: %p)", ictx);
 
@@ -1676,7 +1676,7 @@ ngx_proxy_wasm_instance_invalidate(ngx_proxy_wasm_instance_t *ictx)
 
     while (*root != *sentinel) {
         n = ngx_rbtree_min(*root, *sentinel);
-#if 0
+#if (NGX_DEBUG)
         pwexec = ngx_rbtree_data(n, ngx_proxy_wasm_exec_t, node);
 
         dd("invalidate root ctx #%ld instance (pwexec: %p)",
@@ -1684,7 +1684,6 @@ ngx_proxy_wasm_instance_invalidate(ngx_proxy_wasm_instance_t *ictx)
 #endif
 
         ngx_rbtree_delete(&ictx->root_ctxs, n);
-
 #if 0
         destroy_pwexec(pwexec);
 #endif
@@ -1734,10 +1733,8 @@ ngx_proxy_wasm_instance_destroy(ngx_proxy_wasm_instance_t *ictx)
         rexec = ngx_rbtree_data(n, ngx_proxy_wasm_exec_t, node);
 
         rexec->ictx = NULL;
-        rexec->started = 0;
 
         ngx_rbtree_delete(&ictx->root_ctxs, n);
-
 #if 0
         destroy_pwexec(rexec);
 #endif
@@ -1754,7 +1751,6 @@ ngx_proxy_wasm_instance_destroy(ngx_proxy_wasm_instance_t *ictx)
         ngx_wasm_assert(rexec->ev == NULL);
 
         rexec->ictx = NULL;
-        rexec->started = 0;
 
         ngx_rbtree_delete(&ictx->tree_ctxs, n);
     }