I am playing on the newer slim version of the PS2. It seems to be consistent with this one location, even when I reload or when I tried to get to it first on start up. It just seems like it only happens in the Biker buildings.
Fortunately, I made it past this section by just throwing the moltov cocktails around the building until the vehicle blew up and the gang members died. By the time I got inside I was on 6 star.