Check it out ... Ben and Jen were seen showing a little PDA Thursday while leaving Ben's daughter Violet's high school graduation ceremony in L.A. However, the duo looks very uncomfortable ... or at least they do in a few of these shots, which look uncomfortable.

As you can see ... Jen was looking at Ben with a serious expression at one point -- and, if a picture's worth a thousand words, this one certainly seems to spell out an essay.

Of course, it's possible Ben and Jen -- who are still living apart, BTW -- were just trying to keep things cool and calm ... as they were joined by their respective kids for the outing. Ben's mom Chris and ex-wife Jennifer Garner's mom, Pat, were also in attendance.

Despite the physical touch here, Bennifer left in separate vehicles ... later returning to their current residences, separately. In other words, Ben slept at his own crib ... and she went back to their L.A. home.

Remember, as we previously reported ... Ben is currently residing in Brentwood ... instead of the Beverly Hills pad he and Jen scooped up for $60 million last year.

Neither Ben nor Jen have publicly addressed the state of their marriage at this point ... sending all sorts of mixed messages recently. Ben has ditched his wedding ring a couple of times amid the separation rumors ... while Jen was seen house hunting earlier this month.

Still, the couple continues to step out with one another time and again ... proving they can at least stand to be in one another's presence. Now, we're seeing them show a little affection.

Ben and Jen have had quite the rollercoaster romance ... first linking up in 2002, after costarring in "Gigli" together. The stars got engaged shortly after ... later breaking up in 2004.

Fast forward almost 20 years later, when the exes reunited ... choosing to get engaged again in 2022. They had a Las Vegas wedding that same year ... celebrating their nuptials in a more formal wedding at Ben's Georgia house. It was a full-circle romance ... until now.