diff --git a/sys/net/application_layer/gcoap/forward_proxy.c b/sys/net/application_layer/gcoap/forward_proxy.c
index c2bf37ef87de..afe811f6c6ec 100644
--- a/sys/net/application_layer/gcoap/forward_proxy.c
+++ b/sys/net/application_layer/gcoap/forward_proxy.c
@@ -276,6 +276,9 @@ static void _forward_resp_handler(const gcoap_request_memo_t *memo,
     /* No harm done in removing a timer that's not active */
     ztimer_remove(ZTIMER_MSEC, &cep->empty_ack_timer);
     buf_len = coap_get_total_len(pdu);
+    assert(memo->state == GCOAP_MEMO_RESP ||
+           memo->state == GCOAP_MEMO_RESP_TRUNC ||
+           memo->state == GCOAP_MEMO_TIMEOUT);
     if (memo->state == GCOAP_MEMO_RESP) {
         uint8_t req_etag_len = _cep_get_req_etag_len(cep);
 
@@ -304,6 +307,7 @@ static void _forward_resp_handler(const gcoap_request_memo_t *memo,
             }
 #endif
         }
+        _set_response_type(pdu, _cep_get_response_type(cep));
         /* we do not need to check if valid came from upstream as this is already automatically
          * converted by the client-side to the cached response */
         /* else forward the response packet as-is to the client */
@@ -315,8 +319,13 @@ static void _forward_resp_handler(const gcoap_request_memo_t *memo,
         assert(buf_len >= (sizeof(*pdu->hdr) + 4U));
         gcoap_resp_init(pdu, (uint8_t *)pdu->hdr, buf_len, COAP_CODE_INTERNAL_SERVER_ERROR);
         coap_opt_finish(pdu, COAP_OPT_FINISH_NONE);
+        _set_response_type(pdu, _cep_get_response_type(cep));
+    }
+    else if (memo->state == GCOAP_MEMO_TIMEOUT) {
+        /* send RST */
+        gcoap_resp_init(pdu, (uint8_t *)pdu->hdr, buf_len, COAP_CODE_EMPTY);
+        coap_opt_finish(pdu, COAP_OPT_FINISH_NONE);
     }
-    _set_response_type(pdu, _cep_get_response_type(cep));
     /* don't use buf_len here, in case the above `gcoap_resp_init`s changed `pdu` */
     _dispatch_msg(pdu->hdr, coap_get_total_len(pdu), &cep->ep, &cep->proxy_ep);
     _free_client_ep(cep);
diff --git a/sys/net/application_layer/gcoap/gcoap.c b/sys/net/application_layer/gcoap/gcoap.c
index 2e9d4e7e460a..86272c7622a9 100644
--- a/sys/net/application_layer/gcoap/gcoap.c
+++ b/sys/net/application_layer/gcoap/gcoap.c
@@ -1045,7 +1045,9 @@ static void _expire_request(gcoap_request_memo_t *memo)
         /* Pass response to handler */
         if (memo->resp_handler) {
             coap_pkt_t req;
-
+            memset(&req, 0, sizeof(req));
+            /* 0 means there is an observe option value */
+            coap_clear_observe(&req);
             req.hdr = gcoap_request_memo_get_hdr(memo);
             memo->resp_handler(memo, &req, NULL);
         }