Ubiquiti APs failed this test. The moment one started an OTA update, my mom temp unplugged it to make room for a blender. It soft-bricked itself. Parents couldn't figure out how to reconfigure it after a hard reset.
Took awhile to get the approval but when you have a large pile of RMAs sitting for 6mo to a year due to a bad firmware update, for only a standard 1-2 year limited warranty, and they stop responding, and replacements were back-ordered for ages. Well, you do what you have to.
Usually the power brick is poorly isolated and/or you have dirty electricity, it results in errors on an ongoing basis that get logged to the small amount of onboard memory. (not usually a circular buffer.)
When the errors have sufficient volume the memory fills up, and it stops working at resource exhaustion.
In a real pinch, I've resolved this in some of the more milder cases by simply using one of those walmart plug timers that turns off for a few minutes in the morning when everyone is asleep.