

Because, unless you’re driving a forklift, the point of a vehicle’s rotation is in line with the rear wheels, meaning you can take turns at a much more acute angle when reversing than going forwards. Which makes backing into spaces much easier.
Notice that most of the half-assed parking jobs you see are generally people who have driven forward and left the car parked at a diagonal half out of the space, because getting the vehicle lined up in that situation is more difficult.
As others have said, 100% a leak.
I would advise to stand on a chair or stepladder underneath the ceiling and check to see if it is still level. If you see an obvious deformation around the stain, this will be being caused by water pooling on top of the ceiling plasterboard. In which case, once the leak is sorted, you will likely need to drain the pooled water, cut out the damaged section, replace it, then replaster and repaint.
We had exactly the same issue in our last house. It was in a difficult to see spot hidden behind our kitchen cabinets. We only realised the severity of the issue when the ceiling boards gave way and fell on my head.