Accidentals disappear on selection of range

I am arranging a piece that makes heavy use of accidentals. If I select a range on on part, all of the accidentals (in this case, all sharps) are removed, and the notes in the selected region become naturals. This is further compounded by the fact that there is a linked staff (Tab simple), and the change prompts the movement of the tab notation to a different string (the solo is played in the 12th position, but the move changes the string to try and play in the first position).

This is a new score that has been started in MS4, it was not ported from 3.
The version is the most current as of today
OS: Windows 10 Version 2009, Arch.: x86_64,
MuseScore version (64-bit): 4.0.0-223472200, revision: 5485621