So much for giving vague reasons about “creative differences.” In February, the shocking news came out that “Scream” star Skeet Ulrich, 50, was leaving The CW’s “Riverdale,” where he plays gangster-turned-sheriff FP Jones. Usually actors give politely vague reasons for TV departures, but Ulrich’s gloves came off in an Instagram video he posted Wednesday night. …
Novice directors don’t usually get advice from the legendary David Lynch — unless you’re “Riverdale” star Madchen Amick, who makes her debut behind the camera for Wednesday night’s Season 4 finale. “David [Lynch] actually sent me a really sweet email the night before my first day of directing,” Amick, 49, tells The Post. “He said, …