Law enforcement sources tell TMZ ... one of Lee's staff members stopped by his Los Angeles area home last week to find the place ransacked. We're told the thieves smashed a sliding glass door to get inside the house.

The incident, we're told, went down while the "Squid Game" star was out of town ... but it's unclear what, if anything, was stolen and how much those items might be worth. Cops say Lee will go through his belongings when he gets home to figure out if anything is missing.

Our law enforcement sources tell us cops don't believe Lee was targeted here ... instead, police say this appears to be the work of one of the burglary crews that have been robbing wealthy neighborhoods around Los Angeles.

One of those recent smash-and-grab burglaries involved Lena Waithe ... as we first told you, Lena was hit for around $200,000 in jewelry when thieves broke into her home while she was out of town.