My normal girl is a great eater but she does something similar. I thaw out the mouse and get it very hot and dry. Then I dangle it in front of her and she constricts, but after she lets go she seems hungry but seems to have no idea where the mouse is, even though it is in front of her. So I always have an extra glass of steaming water ready, take the mouse out, dip it in for a few seconds, dry it off, and she constricts again and eats it the second time. I guess it just cools off too much while she is constricting (she constricts forever).

That may stress out a shy snake though. She doesn't seem to care about anything.