@bravenel@gopher.ny On a C8 after updating to 2.4.0.151 the total app run time greatly exceeds the uptime. Didn't think to get a screenshot, but it appeared to be the total app run time since an automatic reboot overnight.
After a reboot, the total app run time is close to the time between the update and the reboot.
It appears that the value is not reset properly during the bootup process.