OK, lets take EXACTLY THE SAME model of clone - A&W 08207:

and it's... DIFFERENT from other A&W 08207 that I use here!

PCB looks different, number of signal that go to keyboard is different (18 vs 16):

So still no reproducibility yet, but PCB has name on it and it's 350ms (even though flexible circuit says 82MS-9R) - so it might be clone of CASIO fx-350ms (that should have the same face as well)? Stay tuned to find out...

P.S. It looks like 2 additional contacts on the left is RESET (in the center on the back), but in the same time other 16 contacts connected to keyboard matrix very differently!