Trying to add an "E" note but it keeps turning into a crossed note?

I'm trying to add a note, but when I click the line to add the note, the note turns into a cross and shows up as on the 2nd line of the staff (but still makes the "E" sound). I've tried deleting the measure, editing the inspector and measure properties, and restarting Musescore with no luck.

Is there another way to fix this issue?
Thank you!