I'm really very sorry about this regression. I fixed it earlier today already here: https://git.zx2c4.com/wireguard-apple/commit/?id=20bdf46792905de8862ae7641e50e0f9f99ec946 but now we're stuck having to wait for Apple's review of the fix. This is as frustrating for me as it is for you.
As a temporary work around, try adding a DNS server to the [Interface] section : [Interface] DNS = 8.8.8.8 Let me know if that gets things working again.