Hello and thank you for the post.
Could you post the link here to the video as this would be great to share with others?
I do agree with you with regards to triggering on CAN signals unless you know what glitch to expect and where.
Auto trigger would have been selected in order to stabilize the signals on screen (which is of real benefit for new users)
The Auto trigger will wait for the trigger settings to be compromised for a specific time only.
If the trigger conditions are not met PicoScope will display the waveform regardless of the trigger settings so allowing data to be viewed onscreen (Once again, ideal for new users who find themselves with a real CAN fault on first connection)
I hope this information is of some help, take care.......Steve