Haggis was sued in December for allegedly raping film publicist Haleigh Breest in 2013 at his apartment after a movie premiere. Haggis denied the claims and countersued ... alleging she tried to score a $9 million settlement out of it.

Still, Breest's suit reportedly led to 3 new women coming forward with their own claims of sexual misconduct -- one similarly accusing Haggis of forcing her to perform oral sex then raping her.

Haggis had previously said he's used to defending himself against 'false allegations' because he's a notable critic of Scientology. He famously left the church in 2009 ... and appeared in the 2015 documentary 'Going Clear' about his experience.