Adobe Animate 2024 onion skin only working forwards

Hi All,

This is killing me as it has been working right up until the last few weeks. I have been into the advanced settings and make sure they are set to show 2 previous frames and 2 future frames (although I do not need future frames for my tasks) I am simply drawing on top of a copy of previous frame after inserting it as a keyframe (so the normal way). So clearly what I would like to see is the previous fram so that I can change the mouth slightly etc and still make sure it all lines up. 

The issue is wierd because it works the other way just fine; I can see the frames that are coming.(I have toggled the "show keyframe only button..." makes no difference) Check out my settings in onion skin below (they are basically the default settings).

I have been copying previous frames in front just to draw and then deleting them because I can't see the previous frame) (what a hassle)

Any help would be much appreciated.