Kris Jenner -- Smiles Through Split ... While Bruce Rages On

You'd never know Kris Jenner just got separated from her husband of 22 years -- not based on her ear-to-ear grin after dinner last night, anyway.

It's becoming Kris and Bruce Jenner's M.O. -- she smiles like nothing's wrong ... while he lashes out at every paparazzo who comes within 20 feet.

So, we had to ask Kris if their separation really is mutual -- as they've been telling the world.

Meanwhile, just a few hours before we shot Kris ... Bruce was busy doing his thing -- threatening to run a photog, not one of ours, off the road.