Issues with exporting score and parts

I've had an issue with exporting parts and score on Musescore 3. I have Mac OS 10.14.2 on my iMac, and I did not have this issue with Musescore 2. I have created a combo score for my group, and when I export the individual parts, it works without any problems. Unfortunately, I've been sharing the Score and Parts file, which is what is having problems. This program creates files using random non-musical symbols on the staff. This issue appears with this file every single time. I haven't had a chance to test it with other files (because I'm hesitant to spend time creating another file on MuseScore 3 if it's also going to be faulty). Any help with this would be much appreciated!