It does not happen when driving over a hill. There are two different levelling functions. What you describe is the "homing" procedure for the stepper motors (typically) that do the levelling.

Static levelling is mandatory for HID headlamps, and that adjusts the headlamp level according to load, etc, for example based on suspension level sensors. As the name says, it is static, so it doesn't do anything while the vehicle is moving.

Dynamic levelling compensates for driver braking and acceleration, but I have not seen a production system that works for hills (how could it without information about where the crest is?). Typically, the systems work to ONLY react to the driver doing something, not road features like speed bumps or inclines.

Neither levelling procedure works to actively reduce glare for other drivers when in turns or going over a hill.