Interesting. Certainly sounds like an issue but as you say whether it's *the* issue is the question. Also interesting that the same item killed multiple motherboards in similar ways even though they were different (well two were)
I also bought one of those Philips UHD monitors after your review

although it seems it's not really a monitor issue. If it takes out my laptop though that's not going to be a good thing (or maybe it will since I can upgrade

)
I don't usually turn my laptop off though when it's plugged in. I have had the odd seemingly handshaking type issues when plugging it in hot.