Hello. First, let me commend you on such fine apps. I have the Nature 425 piece & the Arctic 425 piece. The Arctic puzzles work fine.
The Nature puzzles have a glitch with the inside pieces not “clicking” onto their correct border counterparts. I’ve noticed this with the very first picture, especially. (The settings are on for them clicking together.)
The borders click together.
The inner pieces click together.
Just not the inner ones to the border.
I bought this on Amazon underground for my kindle fire 8 (2016).
Thanks for your time. BTW, I did notice that once the puzzle is saved and the app exited, going back into the puzzle has all the pieces clicked together that are supposed to be. Continuing on with the puzzle, the same glitch happens again.