Soundfonts are removed from synthesizer on closing MuseScore
I've only seen this glitch (?) since the 3.4.1 update. This has nothing to do with score editing itself and can be reproduced whether there is a score open or not, so no attachments should be necessary. Steps:
1) Open any score (optional)
2) Load soundfonts into the synthesizer (example: M.S. General HQ, GeneralUserGS)
3) Close the synth; the soundfonts will play normally
4) Close MuseScore and reopen any score
5) Open the synthesizer. The soundfonts must be reloaded.
I'm not sure of this is a glitch or by design, but I didn't have to reload my soundfonts before the latest update.