Horse is stuck between two different weights (resolved)

[Cypress Creek Elites]

Hi! So I've been aging and comping my horse https://www.horseworldonline.net/horse/profile/3520796 and I recently noticed that his weight would only fluctuate between 297lbs and 311 lbs. He would go up to 311 if I left him on pasture for a turn, but he would not gain weight in a barn, even on 105%, 110%, and 115% feed (not in the red) over multiple turns.
I'm going to play around and see if I can get him to gain more weight in a pasture and see if that'll fix his issues, but I'm really just kind of baffled. I don't know what's going on.

[Cypress Creek Elites]

So I was able to get him to lose additional weight but now I'm trying to get him to gain weight past 297 again (in a barn) and he finally did.
Still don't know why it happened in the first place, but it's all good now xD