Unable to move down a string in linked TAB when using 8va on staff

Composing for electric guitar. Top staff is a staff while the bottom is simple TAB. TAB is linked to the staff.

When I put an 8va on the staff, the linked TAB forces you to use the highest possible string. If you move the note down past the range of a string, only then does TAB move to the next string.

Neither dragging the number via mouse nor command+down work. But both count as actions in the undo-redo memory, even though nothing happened.

workaround: don't use 8va. Or perhaps use unlinked staff and TAB. I recommend unlinking them after the score is done and you are doing your final touches.