Response SMTPE gateway missing time changes

Hi there, we have a Response SMTPE gateway and an older Net3 Show Control Gateway on our network to interface with an Eos RPU3 and a Gio@5. In the show each track starts on a different timecode hour, each set with a 15 frame (0.5 second) offset to allow the gateways to recognise the time change. The Net3 gateway is working as expected, which is true of 3 other productions around the world using the same set up. The new Response gateway is mostly keeping up but at least once per show will not lock into the timecode change for a couple of seconds. By which point, cues have been missed. 

The time it takes seems to be random and we cannot recreate the problem consistently. I do not believe it to be a networking problem as the gateway continues to respond to ping queries when the problem is occurring. Also both gateways are plugged into the same switch but only the Response gateway has the problem. 

I have updated the Response gateway to the latest firmware which has helped the issue (before it could take up to a minute to lock in) but it has not fixed the problem entirely. We have also swapped the audio feeds between the two gateways to see if it was a problem from sound but the results are the exact same. 

Is this a known issue with the gateways or is there any other diagnostics we can check?