We have always had good adhesion, but suddenly peeling has occurred. What should we do?

Ink attached so far but it suddenly peeled off. I don’t know what to do.
Please check the following.
(1) Film thickness of printed ink layer
Thinner binder layer tends to have weaker adhesion.
(2) Drying conditions for printed ink layer
If ink doesn’t dry sufficiently, the strength of the printed ink layer becomes weak and cohesive fracture will occur.
(3) Are there any additives such as defoamer contained in ink or binder?
If additive such as defoamer is added in ink, ink’s adhesion to resin tends to be weak.