In fact if it was actually reaching 143 C, I'd say that ironically I'm more positively impressed by the fact the hardware works at all at that temperature than I am negatively surprised by the fact that its thermal controls are that bad.

The heat problems are real. I mounted one to the underside of a cabinet, and it melted the plastic lining on the opposite side of the wood. They run extremely hot.

For completeness, that was when the summer sun was shining directly on the enclosure in the hottest part of the day, during a country-wide hot spell. Still, no airflow, heat generation, etc.

Every day, cut out. When it cooled down, it worked again. This continued for about two months, then they failed.

Sure that's kind of a worst case scenario there. One of the bigger problems with the ER-L design, IMO, is that they don't have any sort of temperature measuring device inside the case itself. They run hot even without extreme ambient temperatures so you'd think there'd be some baked in way to monitor the temperatures, but no.

If memory serves the ER-L idles at around 40C exterior temp. That was the primary reason I went with the ER-X despite hooking it up to a gigabit uplink.