set_max_skew giving path not found warning

Hey,

I have the exact same problem. https://community.intel.com/t5/Intel-Quartus-Prime-Software/Crossing-Clock-Domain-Problems-Timing-Analyser-ignores-set-max/td-p/1308590 .
However it works during the place and route and also the designs output is correct. I can not detect any metastability.

Am I right assuming that this error just occurs while using the Timing Analyser and no error is thrown during compilation?

Sadly I also got no answer as do other people with the same question (looking through the forum it gets asked at least once a week I would say).

Best regard
Christian