Yep figured this out yesterday. I had been tagging G type instances with an alarm as a fail safe if the AWS autoscaler failed. The alarm only stopped the instance and didn't terminate it (which deletes the drive). Thanks anyway CostlyOstrich36 and TimelyPenguin76 🙂

It's an interesting question!
I think that the instances are terminated when they are spun down therefor the behavior should be the same as if you terminated them yourself manually

Hi RobustRat47 , the volumes should auto deleted

Okay, I'm going to look into this further. We had around 70 volumes that were not deleted but could have been due to something else.