Groupmaster active when updating cue - > output jumps

Recently I've tried updating a fixtures intensty while habing a Inhibitive Group Master active with a level of 90%

When the fixture is selected and lets say I want to take 1 % off its level, the output jumps immediately to -10% of the original intensity. It also happens when you've just 'touched' the wheel(without changing the intensity in %)

You should be able to edit levels in a group of fixtures when a groupmaster is active without jumps or bumps.

So when a fixture is in in a Groupmaster it should be editable smoothly to take just those % off.

Anyone has a familiar experience?