MuseScore added a random staccato-like effect on a note that I didn't touch

I was creating a score and listening to playback. The problems started when I realized the tempo needed to be faster on a specific part of the piece, so at the beginning of it I added several metronome markings to create a speeding up effect on playback, that I would eventually hide. The marking before that section was quarter note = 138, but this section was in 2/2, so I set the first marking to half note = 69 and the last of the series to half note = 80. However, when I listened to playback, there was a random quarter note that had an added staccato-like effect to it! The note barely played before stopping, and I had no idea where this was coming from (I have attached an image with the note being played staccato in red. I have several instances of this pattern on the left hand, and all are affected by the problem). I have tried adding a legato there, and also adding a staccato then removing it, but none of this worked. I tried changing the tempo back to the slower half note = 69, as well as to quarter note = 160 and even back to the original tempo of quarter note = 138, but none of this worked. I have also tried closing the file and restarting the program, but again, that didn't work. Any ideas to fix this? I haven't used MuseScore all that much, and I don't know where this bug could be coming from.