"Save to Score" in Synthesizer for scores created in MS 2 doesn't work as of latest update

I've been editing old scores and everything was find and dandy until recently, when the synthesizer settings I've been using (FluidR3Mono_GM.sf3 with reverb mix right in the middle) stopped saving. What I mean is, I can change them just fine, and when I press the "Save to Score" button it shows the asterix* in the filename, but if I save and close the score, then quit out of Musescore, then reopen it so the synthesizer is at the default Musescore 3 settings, "Load from Score" does absolutely nothing. Opening a score I've saved before the latest update and doing the same works fine (that is, pressing the "Load from Score" button correctly retrieves the synth settings).
So I tried doing the same with a new score created in 3.2. And it also worked fine. But, when I tried loading the synth settings from the first-mentioned score, it loaded the default settings! So I conclude that the "Save to Score" button, only on scores created in MS 2, for whatever reason saves the default settings to the score regardless of the current settings.