Tuplet bracket vertical positioning bug
Create a tuplet with quarter notes or any other duration that results in a bracket (i.e. longer that eighth notes). Double-click on the bracket and use the arrow keys or mouse to reposition it. The bracket either moves up or down and then continues to move in that direction regardless of which key you press or which direction you move the mouse in.
OS: Ubuntu 18.04.2 LTS, Arch.: x86_64, MuseScore version (64-bit): 3.2.2., revision: c893c61