Certain Instruments sometimes do not playback

So sometimes, when I open or start composing something in MuseScore, certain instruments cannot be heard at all when either clicking on the note in their part or when starting playback. One time before only the percussion and string pizzicatos were playing in an orchestral score that I am transcribing, with none of the other instruments playing at all. Another score I have also only plays percussion with the rest of the instruments (winds) not sounding. A score that I recently started has every instrument except the cello playing back. It probably has something to do with a new .sf2 file that I have been messing around with because before adding it to the synthesizer nothing like this had happened. Even then, whether or not an instrument is affected seems to be completely random.

Edit: I tried resetting all preferences to the factory default and it did not fix the problem.