Automatic gear shifter issue

[Kompressit]

Hi There, can anyone solve this puzzle? My gear shifter works OK most of the time, but on occasion with the break pedal held down the shifter won’t move out of drive. As soon as I lift my foot off the brake pedal the shifter moves fine. Since the issue seemed related to the brake pedal I replaced the brake pedal switch, but still the same issue. Bearing in mind that most of the time the shifter works as it should, any ideas on what’s going on? Thanks.