I've had 1 out of 3 die so far, even with replacement with a higher rated PSU. At idle with 0 POE devices, I see temps of ~70c, perhaps contributing to premature derating and maybe in the long run is probably why it's dying.
Two other units however are running at the same temperature ranges but still going strong. I wonder if it's an issue with the switch components drawing down on the PSU past the rated current, thus killing them?
If I didn't have a bunch of spares, I'd probably have went with the external PSU idea, or at this rate I'm thinking a small 4CM fan placed directly over the PSU might help prolong things.