Go to the humanoid. Somewhere in their, there’s a setting that says “Character Auto Rotates”, or at least I think that’s where you find that setting. I was experimenting with this earlier and found it. It could also be that you have a giant invisible ui over the screen that’s messing with the shift lock somehow.
We solved this off the forum, so just in case someone runs into the same issue, basically humanoids hate it when the Humanoid Root Part(HRP) is a perfect cube, so what I did was make the HRP wider and it seemed to work. Not sure if this is a bug, but it seems like a weird fix.