My e36 started doing that occasionally - noticed it maybe 3-4 times. The 4th time I noticed it, my temp gauge was shotting for the red. Was on the 401... pulled over and tried to figure out what was going on. The oil levels seemed fine, no leaks, coolant was topped up... couldn't figure it out.
It was a hot/humid day and I was basically in gridlock traffic. Turns out the fan wasn't spinning fast enough to cool properly. I literally could stick my finger in and spin it the other way while the car was running.
I'm not saying it's a direct correlation, but ever since I got that fixed (been a few months now) I've never seen the flickering oil light again. Maybe it's heat related, maybe it's not.
Take my experience for what you will...