Usually, this happens whenever you are prone between two surfaces that are close together. This happened to me in a Conquest match on Fort de Vaux. I decided to try and activate the Megalodon easter egg. You have to break a bunch of boxes and throw a grenade down a small pipe, among other things. After I did that pipe thing, someone began shooting at me. I went prone behind the few boxes that were left, but I was "squished" between the box in front of me and the box behind me. As a result, it forced me to stand up. I went prone multiple times and every time it forced me to stand up. I got sick of it and broke the box behind me and went prone. It didn't force me up. If you weren't "squished" between two objects, then I don't know what the problem is. Hope this helped you out.
