Time based fault?

bpurbat@yahoo.com

I have a custom project using an 2018 xsr900 and have tuned it with an unrestricted map and that's it. I noticed after "X" amount of runtime, say approximately 10hrs maybe, that the bike was in some sort of limp mode with an 8500rpm limiter. No fault codes. ABS is removed, and speed sensors are disabled. O2 sensor is not plugged in as I'm under the impression it's disabled in the tune anyway. I have the active tune kit just have not installed it yet. I reflashed the ecu back to stock, then back to the unrestricted tune and my problem went away. What could cause this?