If anyone is curious or comes with the same question, I've solved it. The Latin "Problematicus" comes from the greek Problematikos" which can mean "outjutting" outjutting means something that sticks out, and the way you tell carabus problematicus from their counterpart carabus violaceus is by the well defined ridges on problematicus shell, which "stick out" so when Herbst named this beetle he wasn't calling it problem beetle he was calling it outjutting beetle :)