Muscle memory is definitely real. Just curious, from what you describe I wonder where your foot pivot is relative to your round kick. I have seen a lot of flexible people who could kick with the kicking leg in the right position/rotation but pivot their standing leg little if at all. Could this be part of the reversion back to a front kick?
When I did a full chamber, I had to move foot to do the round and I think it throw off my timing.
Your right I only pivot a little from a front kick to round kick.
I think that it was more of a timing thing , than a back foot placement. I think probably in my past, I practice doing a round kick after a half chamber side kick and it triggered a memory, I think probably in the past , I practice a round kick after, a front kick, so it trigger another memory. So then I remembered how it felt and I could reproduce it.
I practice so much yesterday , my legs are very tight all day. They will not loosen up. I can't make up my mind as should I go to class tonight. I am afraid of pulling something or am I using it as an excuse. Tuesday nights is when the women instructor kills my stomach