Autocorrecting in chord fields

I've been using MuseScore for about a decade, and most of my files were created in version 1.3. I recently got a new computer (a Mac running OS 10.14.6), and downloaded MuseScore 2.3.

In my scores created in MuseScore 1.3, if there were 3 chords over one measure in 4/4, I would use a slash symbol to designate which beat repeats a chord (for example, if each beat of a bar is to be played "D7, D7, C, Cmi," I would write "D7 / C Cmi" in the chord fields). When I try to create similar chord progressions in MuseScore 2.3, the "/" symbol autocorrects to "ma." I don't see any way to stop this autocorrect from happening. If I open a score that was created in MuseScore 1.3, all of the slash marks I already had turn into "ma," as well.

I tried just downloading MuseScore 1.3 to create new scores and update my old ones, but apparently the second you try to transpose a score in MuseScore 1.3 on a more modern Mac, the application crashes.

Is there any way to stop this autocorrect from happening in MuseScore 2.3, and/or any hope that a patch could be made to MuseScore 1.3 to stop it crashing as soon as you try to transpose anything? I have almost 200 lead sheets that I've created in MuseScore for my band, and these issues are getting in the way of editing old lead sheets and creating new ones.

Thanks so much for your help!