GBTA on the move. Seriously getting annoying.

Okay, so I've had this large GBTA for almost two months now. Everything has been great with it. It eats readily( It eats almost every day because of the gold striped maroon clown that hosts it and I target feed it twice a week), it shrinks up/inflates on a regular basis, and while it's mouth does open on occasion, it's never swollen and always nice and firm, and it's foot is spectacularly healthy. It was a bit bleached when I got it, but it's regained quite a bit of green pigment since then, varying between tan and faint green depending on what light is on at the time. The problem I have is that IT KEEPS MOVING! It isn't a terribly big problem because the spots it's picking are perfect, but it'll stay there for a week or two, and then move on. It doesn't go too far, maybe a total of six inches or so, but I think my clown is getting very frustrated with it moving, and so am I. So my question is, is it normal for a perfectly healthy BTA to move around this much? It's not affecting any of my corals as of yet, as I don't have any on that side of my tank, but I don't know what else I can do to make him sit still, or if it's just something I'm going to have to live with. Could it just be that my clown is annoying it too much? Or is it still just trying to find the perfect spot?

I also micromanage my tank, checking water parameters every day and do water changes ahead of schedule if Nitrates are higher than 10ppm. Everything else doesn't really fluctuate, but I did have to drop the temp in my tank about 3 degrees over the last week because after rainy day research, I realized my temps were just a bit too high for a new coral I got. Everything else is spot on.