No undo with Synthedit VSTi's

No undo with Synthedit VSTi’s in Renoise 3.3.1
Build jan 11 2021

Decided to make a bugreport, since I really need that ctrl-z.
It is kinda essential for my workflow to try random things and undo them.

Steps to reproduce look like this:

Launch Renoise
Load any old synthedit VSTI (for example VstSpeek3 or Dream64. I’m talkin VSTI from around 2014 here).
Do any action, with any instrument in any part of Renoise. (for example cut/paste)
Hit ctrl-z

Expected results:
Action undone

Actual results:
Message ‘nothing to undo’
Action NOT undone

If needed I can make a video.
You know what is odd? It breaks Renoise everywhere.
I mean if it just broke any action related to the VSTI I could somehow grasp that.
It being code that is more than seven years old, developped with middleware dated back 2005.
But the rather odd thing is that once the VSTI is loaded, undo breaks on a global scale within Renoise,
from the sampler to the pattern editor.
And yes: I tried running Renoise as an admin, even tried compatability mode with Vista.
There are two threads related to this: