Edit: FIRST thing to consider... How old is your AK 550? IS it still under warranty? If it is, taking it to the dealer ASAP is the very first thing to do for warranty service.
Initially I was thinking maybe the computer. But the switching for the hi/lo beam is rather simple and not tied to the computer.
I looked at my color electrical diagram and wondered if your problem might be something within the headlight assembly. This bike does not have separate headlight "bulbs" as is common with factory designed LED lighting systems. The headlight assembly has to be replaced as a complete unit. BUT there is a headlight driver unit that can be replaced separately. That driver unit is a rectangular box attached to the headlight assembly in the center at the top just over 2 silver headlight adjustment screws. Might be able to get to that area by removing the windshield and top cover.
You might also want to verify the integrity of the wiring from the switch to the headlights.
Before going too far... What does the hi beam indication LED do on the dash when the problem is happening?
Here are links to the copy of the electrical diagram and service manual that I have if that will help. The headlights, wiring and switch gear are all in the lower left corner of the diagram. When I look at this document I zoom in at about 300x to be able to read it clearly. Feel free to download these documents as that is the best way to use them. These are valid for the 2020 Euro 4 model as far as I know. I haven't found any more recent factory official documents but I have yet to find any significant differences between this diagram and my 2022 USA model.
https://drive.google.com/file/d/1M48vAJRF57y060p1fRAHnw0bEhk3DBpd/view?usp=drive_linkhttps://drive.google.com/file/d/1M-nAUW1Ay0L6bK50D_EMwYPFT_4-YeDj/view?usp=drive_link
