This is from a write up of Cornered, a 1945 film I’ve never heard of. But this is the part that is incredible, especially since, as everyone knows, there were no communists in Hollywood at the time:

Scott immediately hired the author of The Last Mile and his original choice from the beginning, writer John Wexley. A hard line Communist Party member, Wexley gave the dialogue a distinctly socialist stance, thinly disguised as antifascist drama, much to the chagrin of Dmytryk and Scott. While they too had ties to the Communist Party, Dmytryk and Scott did not want to weigh down the drama with party-approved rhetoric. Wexley was soon relieved of duty, and John Paxton was hired to tone down the Communist propaganda and punch up the antifascist angle, while adding more action and tightening up the pace of the story. . . .

Shortly before Cornered was to be released, Wexley summoned Dmytryk and Scott to a Communist cell meeting where he lambasted them for erasing the Party lines from the film and then demanded their removal from the Red ranks. In effect, Wexley and the Party faithful were upbraiding Dmytryk and Scott for practicing creative freedom. According to Dmytryk, this incident led to him quitting the Communist Party in Hollywood.