I wouldn't worry about the poop, especially since the next one was normal colored. These little ones eat things they find and we don't know about it until it comes out. If he's acting normal and eating, just watch him and don't panic. Also, having the anal gland expressed can cause that as it's the same color as what comes out then. Belle had bright blue poop and upon closer look it was also furry
turns out Mr blue puppy toy was missing an ear! I'm sure it's fine. Just watch. Never a dull moment with these little ones.