Signature track does not react instantaneously

Hey guys.
Cubase 12 Pro user here.

So I’m at the end of a project. All through out working with this project it has been no problem. It just occured when I exported the mix. What I’ve done today is just mixbus processing.

I have a couple of breaks that lasts only two beats, in those breaks I set the signature track to 2/4 and when the break is over I set it back to 4/4.

I have a ducking plugin on the bass, creating that typical pumping bass. This behaves different in different time signatures (in 2/4 each cycle is half as long as in 4/4 = double time pumping). And when I switch back to 4/4 the plugin doesn’t react straight away to the signature change, so the first beat sounds all messed up.

What I’ve tried:

Using two different plugins, TAL-filter and SideKick. Same story with both. So it seems to be a Cubase problem.

Disabling the track and enabling again.

Recreating the bass on a new track.

Closed the project and opened it again.

Closed Cubase and opened it again.

Restarted the computer.

Nothing works. But when I take away the signature changes, the bass is pumping just fine. So I guess that is an emergency solution. But I want to get to the bottom of this.

Thanks!