Do you have some kind of external compressor or something connected. Remember you can only export audio plugins because they are digital. Any kind of analog gear causes the export in real time
There might be an audio interface input or output somewhere in the signal chain, even if you’re not using it.
Check your audio interface channels and routing setups, and see if that’s an issue. These may have reset/re-enabled themselves with the version upgrade.
Had the same problem and it resulted that I was connected to the Loopcloud app from my DAW. Do you maybe have a similar thing running connected to your DAW?
Yes, I am connected to the loopcloud app, I had exactly the same connection in Cubase 11 and I never had this problem. Has something changed in Cubase 12 ?
disabled the loopcloud track and did an export, didnt get the message this time, so didnt export in realtime. Weird though, this never happened with Cubase 11