This happens with w/ a few of my Custom Characters. It’s been a glitch for some of my characters for awhile. If you spam the camera mid-air you get some kind of force applied to your character giving you a speed boost. This can be done effectively while in first person, or shift-lock.
This usually happens w/ custom characters where I have it where the “Head” is bit further away from the “Torso”. You cannot do this while on the ground, but only when midair. So jumping or having your Torso fixed on a y position w/ a BodyVelocity or something.
I made a quick repro of this w/ one of the models I use that can do this. I set it’s WalkSpeed to 5, but you can move much faster by jumping and spamming your camera from left to right.
I’ve seen this happened before with custom characters. I don’t know if it’s been reported before though.
But I think it has to do with something with your custom characters and the roblox physics
Make everything but the center torso/rootpart 0 density. Shiftlock/1st person turning freaks out when welded objects aren’t aligned vertically, changing the center of mass. I had a similar problem when I welded a particle brick to my character 50 studs away.
Yup, you could get the attention of someone on the client team who might be able to take a look at the shiftlock/1st person turning code; it seems like it sets cframe in a weird way and this scenario was overlooked