TimeQuest Analyzer. False unconstrained clock?

You can't false path something the tool considers a clock path. False path only prevents data path analysis on the path, not clock path analysis. If this path is indeed going to the clock input of the IP, you need a create_clock (or more likely create_generated_clock) constraint.

What I don't understand is why a CSR path is being considered a clock path in your design. I haven't used that IP, so maybe you need to check the IP's user guide to figure out what's going on here.