I had a LT with a CC base of less than 1/2". It wasn't enough CC to bother it and it stayed attached to the glass bottom. The tank it was purchased from had a coarse sand substrate several inches deep. The anemone is now in a tank with a 4" DSB
but in actuality, it is in very little sand. The clown has fanned most of it away with his tail forming a large dish shape. When fully inflated, the anemone fills this dish shape but the foot is wedged between some rocks and attached to the glass. It is under MH
lights but I had luck with it under 4 4' NOs in a 55. It sounds like it is unhappy with it's environment. You mentioned another anemone. Many times anemones have fairly large territories. In the wild you never see them close together as you would in an aquarium. Perhaps it is being irritated by the other anemone or other inhabitants. Maybe the lights not quite right. Maybe it was injured during collection. Tough to say. Anemones have one of the poorest survival rates in aquariums. Many folks may post to say they've had one for years with "no problems" but that is not the norm. The sad truth is that upwards of 90% do not last more than 3 months in the home aquarium for a variety of reasons.
You could try removing the CC and slowly adding a sand bed. OR just remove the CC altogether, it doesn't add any benefit to a reef tank IMO