Brow Lamination bleaching brows?

[bre2]

I've been using Lacquer brow lamination and suddenly have a client whose brows seen to be bleaching out? They don't appear to be over processed-they look very healthy, and she uses the brow balm every night. So far she's the only client to experience this and in not sure why. She's received the service 3 times now and after this last one we noticed it happening.