Bug: Unable to update while using VPN

[MDP]

I have been running OpnSense for a couple of years now, 6 months ago I put in a permanent VPN client to encrypt all traffic from my site through Express VPN, while connected to this VPN I have been unable to update (just updated to 20.7 from 19.1.4), in order to find updates and not get a mirror timeout I need to disconnect the VPN client which is less than desirable.

The behavior appears consistent across all version at present.  Happy to assist in diagnosis etc if you tell me what info you need to determine the cause.