I did try this on a simple app as well as several different simulators and yes it's still off. I did notice something odd though... When I add a log file:     NSLog(@"event time = %lf and system uptime = %lf",eventTime,nowTime); and then start tapping rapidly with the mouse in the simulator my output isn't incrementing at the same rate: 2022-07-12 14:57:52.383638-0500 Sample[94195:7441534] event time = 7680.477537 and system uptime = 320019.899535 2022-07-12 14:57:52.466105-0500 Sample[94195:7441534] event time = 7680.479539 and system uptime = 320019.982002 2022-07-12 14:57:52.558809-0500 Sample[94195:7441534] event time = 7680.481744 and system uptime = 320020.074706 2022-07-12 14:57:52.650938-0500 Sample[94195:7441534] event time = 7680.483937 and system uptime = 320020.166832 2022-07-12 14:57:52.760327-0500 Sample[94195:7441534] event time = 7680.486561 and system uptime = 320020.276215 2022-07-12 14:57:52.858784-0500 Sample[94195:7441534] event time = 7680.488940 and system uptime = 320020.374671 It's almost like it's multiplied by a certain amount. Our app has been around for a while and this was apparently an issue in the very very early versions of iOS (ie the code has been around for a long time). If the answer I have to go with is "delete the timing code as it's no longer needed" I can probably get that to fly in house.

Everyone can ignore this. It turned out to be a problem with the Web Access Firewall we were using just deciding to block traffic at some point and not a code issue.