Auto window control setting failed on all windows

Service replaced the faulty air conditioning compressor in my car last week and since then my auto window up/down on all windows has failed, even though the setting is enabled in MFD. I presume they disconnected the battery for an period of time. Phone call to Service suggested I hold down the open switch for 5 seconds after window lowers, then hold close switch for 5 seconds after window closes to reset the auto function. This was repeated for each window.

Problem persisted. Booked the car in for a hands-on fix.

This morning the windows auto function returned spontaneously for all windows after startup. I'm happy, but why?