Sentence examples for a bit of knotty from inspiring English sources

The phrase "a bit of knotty" is not correct in standard written English.
It seems to be an attempt to describe something that is somewhat complicated or difficult, but the word "knotty" is typically used as an adjective and does not fit well in this context.
Example: "The problem was a bit knotty, requiring more time to solve than we initially expected."
Alternatives: "a bit tricky" or "somewhat complicated."