Avoid wrapping back to the first three UDP ports when assigning ports using nextFreeUDPPort because the call resetFreeUDPPorts, called when not interrupting an existing session, will assign the first three ports without checking (or knowing) if they were recently in use.

common.c

@@ -114,7 +114,7 @@ uint16_t nextFreeUDPPort() {
   if (UDPPortIndex == 0)
     UDPPortIndex = config.udp_port_base;
   else if (UDPPortIndex == (config.udp_port_base + config.udp_port_range - 1))
-    UDPPortIndex = config.udp_port_base;
+    UDPPortIndex = config.udp_port_base + 3; // avoid wrapping back to the first three, as they can be assigned by resetFreeUDPPort without checking
   else
     UDPPortIndex++;
   return UDPPortIndex;