At least 18 cast and crew members from NCIS, which is being filmed in Valencia, California, have reportedly been hit with a mystery illness.

The members from the hit CBS procedural came down with a sudden illness Thursday morning, including vomiting, according to TMZ.

A source told TMZ that the members reported “mild symptoms,” which seem to be due to potential food poisoning, but there has been no confirmation of a cause.

NCIS is currently on its 19th season and recently said goodbye to its lead character, Special Agent Leroy Jethro Gibbs, played by Mark Harmon, according to PEOPLE.

During episode four of season 19, Harmon, who was nearly killed during the season 18 finale, left his job for good, opting to stay in Alaska indefinitely after solving a case.

Gibbs told Special Agent Timothy McGee (Sean Murray) while fishing, “I’m not going back, Tim. I’m not going back home.”

And then Gibbs told McGee that he “could not have hoped for anyone better” to work with over the past 18 years before the partners hugged, closing out the emotional scene.

Harmon told PEOPLE in 2019, “If there’s ever a time where the writers are walking into the room and going ‘I don’t know what to do,’ then I think we all have to look at each other and call it a day. But we’re not there yet.”

Expressing his gratitude for his long-running spot on the show, Harmon said, “I’ve been around long enough to know what this is. That commitment is part of what I signed up for. I know when this show ends that’s it — there won’t be anything else like this for me.”