Title basically explains it.
I’m not able to scroll a normal scrolling frame using the mouse wheel while holding either left or right shift on my keyboard. Dragging the scroll bar with my cursor still works fine while holding shift however. Frame.MouseWheelForward, PlayerMouse.WheelForward and both corresponding Backward events also still fire properly while holding shift.
Reproduced both on the game client and in Roblox studio. This issue also appears to only take effect after a certain control action like movement or camera turning (and probably a lot more) was performed.
This behaviour is new to me so I thought I’d bring it to your attention.