My Cell C phone has an IP address of 197.174.180.230 at the moment and I am experiencing the same problem as before with delays after the 4min "timeout".
Not sure if this is related to IP address range or not.
Will disconnect mobile data connection and try and get an IP in the 41.x.x.x range and check again.
Edit: 11:28
Still unable to get a 41.x IP address.
Have now got 197.171.93.33, with the same delay problem.
Edit: 12:05
Now have IP address 41.53.144.97 and not seeing the delay problem at the moment.
Is this coincidental or is there an issue with IP range differences?
Perhaps other testers can add their IP address to their observations, if possible.
Edit: 22:36
Back to IP address 197.170.219.114 and it's broken again!
Will check again in the morning.