I wonder how long you've been riding this particular horse?
The reason I ask is because I think it takes time for the horse to get to know you and adapt to your cues. Dare I say, I've sometimes found that a new horse needs to come down to my level. Or maybe it IS simply that they don't know me and are trying to figure out what is a cue and what isn't.
I've had horses turn when I'm merely shifting around in the saddle. Or walk like a drunken sailor because I ride on a loose rein. Or shoot forward because I moved my foot and I was just repositioning my foot. Then, after a while, maybe a long while, they learn what is a cue and what is just background noise. I am not an advanced rider so I probably have a lot of background noise for the horse to figure out.
But anyway, I used to say it takes a year to know a horse. And the longer I've ridden, now I think it may take even longer. I've had my current horse maybe 2-3 years and I feel like we are finally really becoming a team. She was always a good horse that I loved and trusted. But I feel like our communication is a lot better now and she knows what I expect from her and she knows what to expect from me. She knows when I ask for something and when I'm just trying to straighten out a slightly crooked saddle.
There are horses that are just super, super sensitive. I am supposing they were started by a rider that every little movement meant something. But I am not that finesse-ful in my riding and it seems like that handful of horses I've ridden over the years have adapted. I've had some you really didn't want to move your legs around on, they were so sensitive.
I think feeling muscle movement goes both ways. Like if a horse tenses his muscles, you can definitely feel it, right? So why wouldn't the horse feel it when we turn or stiffen a part of our body? I think it's not whether they can feel it, but whether they react to it when they don't need to. You sound like you have a sharp, in-tune horse who really wants to be a partner with you.