Currently when you try to scroll using the Scroll slider in a ScrollingFrame parented to a SurfaceGui the slider is very unpredictable. It can be very out of sync with the mouse movement, sometimes moves in the wrong direction from where the mouse is moving, sometimes instantly goes to top or bottom by just clicking and holding the slider without moving and sometimes get stuck so you can only go up or down.
Here is a video demonstrating the current behavior
My guess is that this started happening sometime during the past 2 months but i’m not sure. It hasn’t always been like this atleast. The bug can be reproduced with this model: ScrollRepro.rbxmx (143.4 KB)