Bitwarden ERR_NETWORK_ACCESS_DENIED problem on Win10 - but not when PIA is connected!

This is a strange one (and I think it is related to Electron apps, not just Bitwarden). Basically, if I have no VPN connected (or am connected via NordVPN, which I’m trying out) it launches and opens my vault. But attempting to sync gives a failure message, and checking for updates results in:
Bitwarden Electron Network Error

But if I connect via PrivateInternetAccess, it all works correctly! So… no VPN – it fails. PIA VPN – it works!

And FYI, my Bitdefender firewall rules allow BW full access, and the Edge BW plugin does not have issues syncing regardless of VPN or not.

I don’t know if this is a lower-level network issue on Windows 11, which PIA is overriding somehow and NordVPN doesn’t… but I’m at a loss on this one.

Any ideas would be appreciated… thanks!