Strange Samsung Galaxy SII power button issue

I am still using rather old Samsung Galaxy SII because it is a pretty decent and reliable phone.

(I have been eyeballing Nexus 4, HTC One (Google edition) or Oppo Find 5 lately for my next phone but just haven't got to the part of actually spending a large amount of money)

About a week ago my Galaxy started to act strangely; the power button didn't seem to work properly and locking the phone didn't work all the time - sometimes immediately and sometimes after waiting for a while. Since there are a lot of lockup/screen off widgets to choose from this wasn't a problem until this morning... As the battery ran empty last night I had to actually power on the phone this morning. To my surprise the phone would not power on and I tried all kind of strange instructions that Google provided for a good part of the morning.
My first (logical) though was that this is a mechanical issue... although I consider Samsung quality to be extremely good.

Later in the evening I started thinking that maybe it is time to try the old computer repair trick: take off all the components/peripherals in order to rule them out. Components? Well SIM card, memory card and battery pack (I have a spare one) are those :-)

After trying all combinations (remember to take out the battery in-between trials) the problem was easily located: original (SII+ supported) Samsung's own 32 Gb Micro SD (class 10) was causing the power button to malfunction.
Now that is truly strange... memory card equals power button... duh... not
The card has been working properly but it is clearly the source of  the problems as all the symptoms have vanished (it required also factory reset as some app data was located on the card).
At work we have seen few corrupted USB memory sticks and many corrupted PC memory kits several years ago but not too many corrupted external SD cards; just one comes to my mind - one corrupted SDHC card (ADATA's) 32Gb class 10 for Raspberry Pi about five months ago.

IMHO: One of the best things with Samsung (and most of the Android) phones is the possibility to change the battery; I use my phone as a Wifi hotspot (tethering) many times during the day and carrying an extra charged battery is the easiest way to solve the battery drain issue that sharing connection causes. Most definitely I would hate to carry one of those clumsy external battery packs!