BUG: Absolute Effect using minus value overrides curve in patch when value would go below zero

Found what I’m pretty sure is a bug in 3.0.2 today. 

I have a rig with a large number of orbis fly (RGB spheres on winches), and because they aren’t all hung at the same height, are patched with a curve on the position attribute which is used to set the in and out deads to match all the units.

I was setting up some effects today and was playing with an absolute effect with 2 steps: Background and +-30

If the background position is set above 30 the effect runs as expected, but if the background position is under 30, instead of the fixtures stopping in their patched (via curve) ‘up’ position, they get to the ‘up’ position as set by the curve then snap to their real world (DMX value 000) position, ignoring the curve until the effect starts to bring that channel back down again.

I didn’t have a chance to explore further and see if it affects other attributes or even if it affects the top of the curve as well as the bottom.