JUCE7 plugins causing extremely laggy UI in Ableton Live on Windows7

I’m getting severe UI issues with JUCE 7 plugins running on Ableton Live on Windows 7. As soon as the plugin GUI is shown, the entire Live interface become very sluggish and laggy. Both plugin meters and Live’s own meters become unusable slow (looks like a 5Hz refresh rate - ish). It’s not related to CPU usage. Even moving the plugin window itself around when playback is stopped is very laggy. When the plugin editor is closed, everything is back to normal.

It doesn’t happen on my Win10 machine, only Win7.
No other hosts seem to be affected, but it happens in both Live 10 and 11.
Tested both with JUCE 7.0.3 master and 7.0.4 develop branch.
Same plugins using JUCE 6.1.2 did not have this problem.

Perhaps related to these:

Anyone else getting this?