Tuplet problem

Hard to tell from just images bit is that in a timesig or 2/4? If it is in 3/4 that rest is needed.
Unless you don't want the tuplet either, in which case you'd jjst have to delete the measure content and reenter it without the tuplet (MuseScore can't convert tuplets into notation without or vice versa). This is where the PDF converter is often causing more work for repair, more time than it would have cost had you just transscribed the piece manually