Outside from that discussion i found something interesting: Trends ("tendencias"), and something in statistics named in spanish as "moda" (the most common elements from gathered data). I apologize to don't explain this correctly and confuse it with patterns.

In gacha as example, one R/SR card can't take the same position more than 3 times on consecutive turns. This happens even when other R cards are available, try it.

Extra stage from gambit event showed an opposing example, i never found a 2;6 entries as correct ones, but i saw 2;4, 2;5, 1;4, 3;6, 1;2, 1;6... and even 2;4 (mirror of the "missing" element). Post a screenshot if you see one.

This is not related with the random system, this time i'm discussing it's results. However, seeing that behavior can help on some situations.