Scott Disick -- Snaps at Pap ... Is There Trouble at Home?

Scott Disick jumped down the throat of a photog -- not because he was asked about rumored troubles with Kourtney Kardashian -- but because the pap messed with something he really treasures.

Lord Disick was leaving lunch Tuesday with Kendall Jenner in Beverly Hills when our guy tried to get to the bottom of the rumors he and Kourtney were having issues ... again.

Scott seemed to ignore the question, but seconds later unloaded on a pap who accidentally backed into his exotic sports car -- making it look like he's really on edge about home issues.

Or he really loves his Bugatti.