The 100% chance to crit on target (PVE and PVP) does not work regularly and occasionally fails to crit, this is both PVE and PVP. This may be related to another bug and not actually the problem at all.
Abilities like pick pocket, premeditation that in vanilla Classic / original TBC had no influence on the “sitting” status of a target do indeed cause the target to stand up. This could be the case with Shadowstep, but when used individually it seems to not influence sitting.
Order of operations on Ambush / Garrote and even occasionally cheap shot / pounce seem to be occasionally wacky where auto attack starts before the Ambush / pounce / Garrote / cheap shot causing stealth to break unless you counter this with a macro to stopattack.
Just some observations of annoying bugs.