diff --git a/sys/net/application_layer/gcoap/forward_proxy.c b/sys/net/application_layer/gcoap/forward_proxy.c
index 808180aeb2776..715de112a2bf4 100644
--- a/sys/net/application_layer/gcoap/forward_proxy.c
+++ b/sys/net/application_layer/gcoap/forward_proxy.c
@@ -76,6 +76,17 @@ gcoap_listener_t forward_proxy_listener = {
     _request_matcher_forward_proxy
 };
 
+static void _cep_set_timeout(client_ep_t *cep, ztimer_t *timer, uint32_t timeout_ms,
+                             event_handler_t handler)
+{
+    assert(!ztimer_is_set(ZTIMER_MSEC, timer));
+    timer->callback = gcoap_forward_proxy_post_event;
+    timer->arg = &cep->event;
+    cep->event.handler = handler;
+    ztimer_set(ZTIMER_MSEC, timer, timeout_ms);
+}
+
+
 void gcoap_forward_proxy_init(void)
 {
     gcoap_register_listener(&forward_proxy_listener);
@@ -88,9 +99,10 @@ static client_ep_t *_allocate_client_ep(const sock_udp_ep_t *ep)
          cep < (_client_eps + CONFIG_GCOAP_REQ_WAITING_MAX);
          cep++) {
         if (!_cep_in_use(cep)) {
-            _cep_set_in_use(cep);
+            DEBUG("gcoap_forward_proxy: allocating client context %p\n", (void *)cep);
             _cep_set_req_etag_len(cep, 0);
             memcpy(&cep->ep, ep, sizeof(*ep));
+            _cep_set_in_use(cep);
             return cep;
         }
     }
@@ -99,8 +111,9 @@ static client_ep_t *_allocate_client_ep(const sock_udp_ep_t *ep)
 
 static void _free_client_ep(client_ep_t *cep)
 {
+    DEBUG("gcoap_forward_proxy: freeing client context %p\n", (void *)cep);
     ztimer_remove(ZTIMER_MSEC, &cep->empty_ack_timer);
-    memset(cep, 0, sizeof(*cep));
+    cep->flags = 0; /* cep->event may be queued - don't touch it */
 }
 
 static int _request_matcher_forward_proxy(gcoap_listener_t *listener,
@@ -406,16 +419,12 @@ static int _gcoap_forward_proxy_via_coap(coap_pkt_t *client_pkt,
     gcoap_forward_proxy_find_req_memo(&memo, client_pkt, &origin_server_ep);
     if (memo) {
         DEBUG("gcoap_forward_proxy: request already exists, ignore!\n");
-        _free_client_ep(client_ep);
         return 0;
     }
 
     if (coap_get_type(client_pkt) == COAP_TYPE_CON) {
-        client_ep->empty_ack_timer.callback = gcoap_forward_proxy_post_event;
-        client_ep->empty_ack_timer.arg = &client_ep->event;
-        client_ep->event.handler = _send_empty_ack;
-        ztimer_set(ZTIMER_MSEC, &client_ep->empty_ack_timer,
-                   CONFIG_GCOAP_FORWARD_PROXY_EMPTY_ACK_MS);
+        _cep_set_timeout(client_ep, &client_ep->empty_ack_timer,
+                         CONFIG_GCOAP_FORWARD_PROXY_EMPTY_ACK_MS, _send_empty_ack);
     }
 
     unsigned token_len = coap_get_token_len(client_pkt);
@@ -439,9 +448,9 @@ static int _gcoap_forward_proxy_via_coap(coap_pkt_t *client_pkt,
     }
 
     len = gcoap_req_send((uint8_t *)pkt.hdr, len,
-                         &origin_server_ep,
-                         _forward_resp_handler, (void *)client_ep,
+                         &origin_server_ep, _forward_resp_handler, client_ep,
                          GCOAP_SOCKET_TYPE_UNDEF);
+
     return len;
 }
 
@@ -482,7 +491,7 @@ int gcoap_forward_proxy_request_process(coap_pkt_t *pkt,
     /* target is using CoAP */
     if (!strncmp("coap", urip.scheme, urip.scheme_len)) {
         int res = _gcoap_forward_proxy_via_coap(pkt, cep, &urip);
-        if (res < 0) {
+        if (res <= 0) {
             _free_client_ep(cep);
             return -EINVAL;
         }