As I understand it, okTriggerIn automatically synchronizes the ep_trigger signal to the ep_clk signal. I’m assuming there’s some sort of synchronizer inside the module.
However, Vivado still needs to understand the relationship between the two signals. E.g., if the ep_trigger is on a different clock domain than ep_clk, is an additional timing constraint needed in the XDC file? Something like a false_path usually does the trick.