I had the same issue years ago on a twin Cessna. I was 19, working for an aviation services company for little money and no training and they sent me out to put a quart of oil in each engine. Right engine no problem, left engine the cap didn't snap in like the right one. Took it off and did it again still felt different but thought it was tight.
Well it popped out on the takeoff roll and a very angry pilot came back to the ramp with a smoking engine. I had the honor of removing the engine cowling and cleaning off the oily mess.
They were not twist in caps they snapped in, I don't know if they use that type any more, This was early 80's. Never made that mistake again.