Workout for one horse not running

I can’t seem to run a workout for my filly Stage Presence. I tried clearing out all the other horses’ workouts and only running one manually for her, but it wouldn’t go for whatever reason. Her fitness has been lagging lately too, so I think that this is probably the cause!

I appear to be having the same issue with View Horse: Warm Surprise

It seems as though this problem is back, for the same horse again