This isn't an issue really but rather just some feedback, an it's to do with going to crouch/prone an standing back up.

I think players would find it more smooth if there was a change stance key assignment, so if you tap crouch you.. crouch, however if you old it down you prone.

Also if you press that key again whilst prone or crouching it'll make you Go from Prone > Crouch > Stand pretty simple really.