Deadpool 3 started filming amidst the ongoing WGA writer's strike.
Actors are allowed to improvise lines during the strike, but the rules regarding writers writing lines for a production are stricter.
Ryan Reynolds, who plays Deadpool and is officially a writer on the film, has previously received a writing credit for Deadpool 2 based on his improvisation skills.
Any deviations from the script by Reynolds could potentially be considered strike-breaking under the Guild's rules.
It is uncertain what a Deadpool movie would sound like without Reynolds' improvisation, as he has traditionally improvised most of Deadpool's dialogue.
The first cinematic appearance of Deadpool in X-Men Origins: Wolverine was filmed during the last writers strike, with Reynolds improvising the character's dialogue.
It is unclear which projects are choosing to film during the strike, with some TV shows shutting down and others working with existing scripts or without writers on set.
Deadpool 3 is one of the first big studio features to go into production amidst the strike, and Reynolds may have to adhere to the demarcation between writer and actor roles for the foreseeable future.