Garmin AutoPause going nuts?

The autopause issue is probably due to the speed you have set. You can adjust it for various speeds, and it's likely you were right at the cusp of the on/off setting. Several use it, several don't.

I'm in the camp that uses the total time, and then records my actual moving time. The autopause feature is just something I don't like.

As for the other issue, not really sure what was going on...

The clock doesn't stop during a race!

I don't use autopause, but I know a lot of folks that do and they fairly frequently report issues with it.

If I'm stopping to use the bathroom I figure I can remember to hit the stop then start buttons.  If I'm just at a stop sign I don't see the point.  As I said above...the clock doesn't stop in a race.  I don't need to pad my own ego and make my rides seem faster but cutting out momentary stops.

I don't use auto pause for running (I'll pause manually) but I do use it for cycling. True, the clock doesn't stop in a race, but when I'm training by time, I don't want time spent at a traffic light to be counted as ride time.

Sometimes I wear my Garmin for HR on my road bike which also has a wired computer and I do note a bit of a lag on the stop/start (and total distance/time) compared to the wired computer.