Soundfonts change instruments in mixer to grand piano

So, I just used the Sonatina Symphonic Orchestra soundfont for the first time, and I ended up having to go into the mixer and change every single instrument from a piano to what they were supposed to be. Then, when i changed it back to the default for the current ver. of MuseScore, many of the instruments' sounds had been changed to seemingly random instruments in the mixer, and I had to change all of those back to what they should be in the default. Is there a way to avoid having to do that? Is that common to all Soundfonts? I looked in the Handbook under Soundfonts and the Synthesizer and found nothing about this. I'd appreciate any help I can get.