I used a ready mixed (and, as it turns out, unmodified) thinset to mud the taped cementboard joints in my shower. It was a pain in the butt to work with, but I've never done this before, and despite that fact that I kept thinking "this doesn't seem right", I persevered.
Then, I came across a q and a that suggested this was not the intended use for this product. Am I completely hooped? Do I have to try and take this all off (not sure how ..) and retape the joins?