I have some player stats I persist including a custom pattern (array of arrays of integers). Data was saved ok but I noticed it was lost between games.
I started by separating profile data into two weak maps to determine faulty data. It turned out that simple stats started to persist between games, as for the custom pattern, it had correct number of elements but the elements themselves were empty. As for the diagnostic string ( same data as array but string)it was not saved at all.
All data was checked for fitness and passed. Pattern worked well during the same session and could be resaved and reprinted. So I think there is a bug outside the session and structures like
array { array{1,2}, array{1,2,3} }
are not currently supported and cannot be persisted between games.
After loading a new game, I receive 2 elements in the pattern array, but information about 1, 2 and 3 is completely lost.
I am not sure if it is Lego only or not. I only used