From bumgenius' website (i wasnt going mad
"My tabs aren’t as sticky as they used to be. How can I solve this problem?
First check for lint in your tabs. You can clean it out with a pin or a fine tooth comb. If it isn’t lint, the hooks may have relaxed. This happens over time when you exclusively line dry. Wash your diaper and then dry it in the dryer on warm heat. Be sure to let the diaper cool completely before using. This causes the hooks to recontract and become “sticky” again."
Hope it helps