[stumped]

we have a fire for kids bundle - that's the 2016 Fire HD 8 with some extra software and a silicone rubber edge protector...
.. because there is no protection for front of screen I decided last week to move it into a folio style case with auto sleep/wake..
I have now tried 2 different cases, a WIZFUN one that I returned thinking it was faulty and a hard shell amazon book style one now in use, both said to do the sleep wake trick.

but they don't.

There ARE magnets in the amazon cover - I can stick paperclips to it, but no matter how I position and waggle it - no joy. I also tried moving the strongly magnetized case from my HDX all over the HD 8 screen but I cannot get auto wake to kick in.

so do I have a faulty tablet or is it not working by design?
AFAIK the fire for kids 2016 bundle was the same hardware as the regular Fire HD 8 (2016). I tried reading old reviews but none mention this feature or lack of..
So I am 0 for 2 on two cases with a 3rd , different make, oneon its way via ebay from China. if that does not work either, I will have to conclude its the tablet , not the cases. then it is a question of "is it supposed to work" or not.

Is there any safe way to run other tests e.g. with fridge magnets. I know that magnets and magnetic storage do not play nice together so I am a bit wary...
Ideally, some kind person out there with the exact same bundle from amazon will give me feedback. or even someone with a regular Fire HD 8 2016. I did have one of those but I sold it, without a case, & now I cannot remember if it had this issue or not..
I have also written to amazon & will update here if I get a sensible reply