As title says.

All of the vanilla Telvanni crab helmets spell the name of the crab as "Mole Crab" (which is also the proper name of the real-life animal). Old TR has inexplicably changed this (or more likely, someone has misspelled it once and everyone has rolled with it) so now we have "Mole Crab" helms, a "Molecrab" creature, a "Molecrab" armor set and "Molecrab" ingredients.

We are obviously not going to change the vanilla spelling, so it would be for the best to follow vanilla and change all "molecrabs" to "mole crabs". This was already fixed in T_Data.