How to reset Keychain "certificate is not trusted" error caused by VPN, without rebooting?

If I turn on (my company supplied VPN access) and then attempt to build with Xcode then that has the consequence that all the dev/distribution certificates in the keychain turn red and say "certificate is not trusted".

Turning off VPN doesn't reset them back and of course re-attempting to build will fail.

However if I reboot my MacBook, then the keychain is back in a good state again.

However as I work remotely I constantly have to flick VPN on and off throughout the day, and having to reboot endlessly is a pain.

Is there something I can do to reset the Keychain's certs to a good state without having to reboot? (and without having to delete them all and re-add them all back to the keychain).

How to reset Keychain "certificate is not trusted" error caused by VPN, without rebooting?
 
 
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