Could just be an upset stomach. The squash may be adding to the color and it is very hydrating so often that will produce excess water passing through.
There looks like some rough bits in there. It could just be a bit of blood from straining which isn't usually a big deal. I would continue offering squash and maybe some more water to help him digest more easily. Keep an eye on it like you're doing though. If it still continues to be unusual in a couple of weeks something else may be going on. My guess is just upset stomach though.
Mirage came out of brumation on April 26. He was doing great. On May 2 he started acting funny. We just redid his tank, and he keeps going into one of his hides. He just lays there. He shows no intrest in food. HELP!