Running without a chain device with a long cage slx mech, only losing the chain on repeated stutter bumps.

Will a short cage mech make any difference?

I don’t know if that will help but are you running an unramped chainring?

Yep. E13 33t.

You may need a medium cage rather than a short one as a short one may not cope with your largest sprocket even if it will handle the range.

Shimano dont make short cage MTB 10spd rear mechs, only long and medium. Would highly recommend using a medium over a long though in a single ring setup.

If you’re losing the chain on stutter bumps, it’s more than likely a shorter mech won’t make any difference, however a chain device will make all the difference as it will stop the chain jumping off the chainring.

if you’re feeling wealthy & can wait till the end of the month how about the “lockable” M985 or possibly wait longer for the xt version.

Is this on a hardtail or a full squish?

a different mech won`t make any difference whatsoever!! …
i had to put a front mech on (as a guide)