[1st time rider]

Hey everyone, so I just got back from a 1400 km trip. It was an amazing trip and the bike did extremely well. (2022 650 ADVentura).  Well I say that but half way through my trip, checking my oil, I noticed that I had none(?).  I had to add 500 ml to get it to a point it would register in my oil check window. Has anyone come across this before? 
I am always diligent about checking the oil and it had always been just above the 1/2 mark in my window.  After I returned home I checked again and all is well.
Disappearing oil is an oddity for sure.  No oil in my exhaust and no weeping anywhere on the motor.  Can anyone help?

Looking forward to your responses/ideas.  Oh, it was extremely hot on the first half of my trip, talking 37-40 c with the humidex

[NMKawierider]

Only a possibility but in hot conditions and higher RPMs combustion chamber temperatures can and often do exceed opium levels which causes per-detonation, other wise known as pinging. On a bike one might not feel or hear this but the result is most often an upsetting of the rings and slow usage of oil..slow enough not to be noticed other then when checked. This is why it's always a good idea in hotter weather to use an octane fuel higher then recommended...and less in colder conditions such as winter months. Otherwise one might look at the valve stems for signs of oil getting by the valve seals.