As you are aware, playback templates have never worked with VE Pro except in very limited usage cases.
The one problem that I care about is If you enable IVP for any staves, then it creates a duplicate instance in VE Pro for each voice.
This thread describes the reason for the IVP problem, and I’ve been tracking this since, but no progress has been made in this area. Still doesn’t work with VE Pro 8 as I would expect since it is a Dorico bug.
There’s a thread that describes a workaround if you are interested in modifying playback xml files that can work. But it’s tedious and if you make a change in instrumentation then you need to update the xml file every time.
There are other problems that I have not tracked closely, relating to divisi. I’ve seen lots of threads about this problem but since I don’t use divisi, I haven’t dug in to the reason for the problem. I suspect it is a similar issue.