It turns out that this has been discussed here since 2010…and on KVR since 2005…
The threads basically say that this is a somewhat known issue with some VST hosts including Cubase, Bitwig Studio and Ableton Live and likely not a JUCE issue at all.
It looks like the solution is possibly two fold: not changing the program if setCurrentProgram() is called with the same index, and also setting a timer in setStateInformation() and not changing the program if setCurrentProgram() is called within about 500 milliseconds. I’ll be putting this in my code base as soon as the coffee takes effect.
Unreal.