Only run the status prohibit timer, if it has been set before.

lib/src/rlc/rlc_am_nr.cc

@@ -631,7 +631,10 @@ uint32_t rlc_am_nr_rx::get_status_pdu(rlc_am_nr_status_pdu_t* status, uint32_t m
   }
 
   if (max_len != UINT32_MAX) {
-    status_prohibit_timer.run(); // UINT32_MAX is used just to querry the status PDU length
+    // UINT32_MAX is used just to querry the status PDU length
+    if (status_prohibit_timer.is_valid()) {
+      status_prohibit_timer.run();
+    }
   }
   return tmp_buf.N_bytes;
 }