OSX CPU Usage crash

I got to crash reports that I’m hoping someone can explain to me.
This is on OSX, the crash log has the following:

Event: cpu usage
CPU: 90s cpu time over 160 seconds (56% cpu average), exceeding limit of 50% cpu over 180 seconds
Duration: 160.19s
Steps: 158

What on earth does that mean?
To the user this is seen as the app quitting.
From the log as far as I can tell it is the CoreAudio thread using the most CPU, but that kind of makes sense.
I’m only seeing this on a very small number of systems though.
I know it is not strictly a Juce question, but I’m hoping that the large number of audio developers here can help me figure it out.