Yikes! I've accidentally trained my friendly Llama to be a spitting Llama

My 6 year old female Trinity has always been friendly and affectionate. She didn't even seem to know how to spit when she was given to me 2 years ago. (she was raised as a lone 4H show LLama ) My alpaca would spit at her if Trinity got too close to her food. Somewhere in the last few months Trinity started spitting at Dolly even if she was no where near her food (but always around feeding time). In the last few months I started clicker training them both to go into the trailer and catch pen. Trinity did great, but maybe I was misusing food (thinking of your last article Marty). One time Trinity was in the trailer, and eaten her reward. I was working with Dolly to get in the trailer, and Trinity spit at me. This happened a couple of times. Yesterday I was haltering her (which she has done well in the past) and she started to spit at me, and I told her no, so she stopped. I got her haltered and walked her around the pasture a bit. Then took halter off, feed them the pellets, and hay, and walked out of the pasture. Trinity walked over, as she often does, and instead of being her friendly, wanting pets self, she spit at me. I told her NO and left. I feel I taught this behavior somehow, but not sure when. Now I'm wondering how to stop it. I don't really like the NO, I want to redirect her somehow but not sure what that looks like. Thanks!