When does an exception becomes considered as an anti-pattern?

As a solutions architect, I design and derive software architect patterns all the time. In that process, I have encountered numerous exceptions. They are mostly considered exceptions due to an incomplete technology landscape such as missing a crucial component due to regulatory requirements resulting in me granting exceptions to these patterns.

My question - When does an exception becomes considered as an anti-pattern? Or is there that "grey" zone?

Thank you.

Nathan Aw (Singapore)