Hey Fargoth. Were you also experiencing this yesterday at the Blackthorn Dungeon hunt?
I was getting it like crazy (also using Pincos). My character literally stops moving. Everything else continues like normal. I can type, say stuff, cast spells or activate abilities just fine. The only thing that would free my movement would be to log out and relog. It was a temporary fix because 5min later, I'd lock up again. I then tried Sacred Journeying out and was able to move. Very odd...
I had overhead health bars off. I don't think I limited my hot bars so I'll give that a shot.
I've had this issue before, right outside of the blackthorn dungeon with zero players or monsters around too...even logging off and relog didn't fix it. I had to sacred journey my character out of the area and then my character was able to freely move again.
Regarding the right clicking to buy items off vendor. I have the same problem lol. As you stated, it works fine if you are near the vendor and say "vendor buy." It also works if you find the vendor, double click him to open contents, manually search for the bag, open bag, then right click and buy your items. If you simply teleport to vendor, right click on map, then try to right click on the item to buy, it almost never works.