Snap to Timeline not enabling

So I have 2 almost identiccal macbook pros 1 from 2021 running M1 chip and the other in the office from 2022 running M2 chip. I have always edited using the 'snap' 'S' function while moving clips around, and I have never had an issue, selecting a clip, moving it and while I move it I choose either to 'snap to timeline' or to not 'snap' by pressing the S key while I have the clip still selected.

Recently on my older home macbook pro it stopped working. I now have to releas the clip I want to move, and make my choice of wether Snapping is on or off before I select and move the clip. However, it still works on the newer offic macbook pro, and I can not for the life of me work out why it works on 1 machine and not the other!!

Any help or ideas would be greatly appreciated