Well, I went to check on my cuttings that I've been storing in a bucket of perlite and thought I'd just check the bottoms for no reason what so ever but curiosity. All of them looked good except one. The part that was in the perlite seems to be rotten. I'm not sure what happened. All of the others are doing just fine. Thinking of cutting the rotten bottom off but it will leave me a 5-6 inch cutting. Any suggestions?

I would cut for sure. Let it callous again and root. It's surprising since this variety is generally an easy rooter but that cuttings looks a bit on the green side.

Cut till you see hard, white, latex-seeping tissue and let callus well.

Agree, there is still some hope..just cut,callus and keep dry. Thankfully we are into Spring, going into better warm up conditions. Sometimes it just takes one untimely watering or cold event during winter for damage to set in. At least you caught it in time.