Okay I did a bunch of testing and have resolved this. No cause for alarm and it has nothing to do with VST. Apologies for chasing the red herring. Causation vs. correlation and all that...
High-CPU began a few seconds after launching, by coincidence, about the same amount of time it took to navigate to DSP Studio and display a VST GUI.
The phenomenon was instead related to:
25.0.105 (9/25/2019)
[...]
4. NEW: Made the program update the 'Total Discs' for all the files in the library at startup (files not marked dirty, so shouldn't cause tagging).My library has approx. 152,000 files. The above new feature surely takes a while to crank through all files for the first time. When I tried clearing the library, with all things the same, the high-CPU never happened. With the full library in place, I just waited out approx. 10-30 minutes (depending on which computer) and the high-CPU subsided. I therefore assume it stemmed from the above-noted new feature.
Suggestions:
1. Tweak things so that one can close the application in the middle of such a background process without causing an apparent "hang" 'til complete, AND it'll resume the needed process when launched again.
and/or2. Display a notification under such circumstances, e.g. "
MC is performing a database operation which needs to complete ... please wait" (or some such).
and/or3. Add a subtle indicator, maybe optional, and not unlike the blue light, which tells users when sustained background database optimization and/or similar unusual operations are ongoing.
Thank you.