Lose power in 5th

[Stewy19_Busa]

Shifted to 5th while cruising on the interstate and it was almost like I hit a false neutral but it didn’t happen until about 15-20 seconds of already maintaining that gear. I did a thorough clean of the chain 2 days ago. Changed oil maybe 400 miles ago. I was shifting gears just holding 5th around 6.5k rpm
I have a 2019 with a full system Brocks alien head 2 and other minor things. Bought it in April of 2023 with 290 miles and have since brought that to 13,200 miles.

[sixpack577]

There is a false neutral between 5th and 6th, and if you don't shift it hard enough, on rare occasion it will slip out of gear.
If that was the only time, and it's working fine now, I wouldn't worry about it.
If it does continue, you will have to repair or replace transmission parts.