It's good that a little excess water is coming out with it. That indicates good
hydration. Sometimes they are a bit messy. That isn't necessarily a sign of a problem. Could be related to diet or just general digestion issues if temporary. Older dragons don't need to eat a ton of food, so eating less isn't necessarily a problem as long as there aren't other signs of issue like lethargic behavior or weight loss. It's good to have a fecal sample checked for parasites at routine vet visits, but if there aren't any other signs of trouble, I wouldn't go out of the way for a check and just wait for an annual wellness visit.