Sneak fails and spell Los
 

This is very odd, but I noticed anytime I try to cast a spell but do not have LOS the next sneak will always fail. I tested this with mrylokar gauntlets and this is consistently happening on a 60 rogue which otherwise almost cannot fail on sneak.

BUMP for other Rogues to comment/test

Perhaps related, perhaps not. I don't know. But every time my rogue is in OT outpost (where he is kos) and I use sneak to access some of the vendors there, the next hide and sneak I attempt after leaving that vendor inevitably fail.

I get the success messages, but I am still, apparently, visible to mobs from the front and/or the back.

Sneak still fails 100% of the time after I interact with a merchant or banker while in sneak/hide. Upon interaction with the npc sneak and hide will break. If I try to reapply sneak, it will always result in a failure message.

These are the only sneak fails I ever get as a lvl 60 rogue.