I installed the 10.18 update last night, and rode a course this morning. The release notes for 10.18 claim, inter alia:
"Fixed crash that could occur when saving the ride."
The first activity save after having installed the update resulted in a crash.
"Set minimum backlight level to retain screen visibility after backlight timeout expires."
Not to my eyes. If I don't have the backlight permanently on, the screen is still unreadable in sunlight.
And I had another spontaneous reboot this evening while I was looking through system settings.