The answer is yes and know it really comes down to how you weight your snakes and it's activity.
For example if you always weigh your snake on empty than yes it's a significant weight loss
However if the first time the snake was weigh right after a meal and the next weigh in occurred after one or more bowel movements than no it is not.
Also is the animal a breeder or just a pet, breeders will lose weight as breeding activity can take it's toll especially if the animal is not eating.
The important is to make sure that the animal is well hydrated and when in doubt have a fecal done to eliminate any possibility of internal parasites.