For some reason, sometimes when I dismount/eject a physical drive, Safari launches in the background. This behavior has occurred even in safe mode, in a guest account, with nothing else running. I've experienced it happening with SD cards, USB hard drives, and thumb drives.
I've spent an hour on the phone with an Apple tech to no avail, and I've spent quite a bit of time on my own trying to narrow it down. What could be causing this, and how can I stop it?
I'm running Sierra on a 2015 rMBP.