BUG:There is a problem with the card type judgment

[Horizon]

When I played four Ace of Hearts and a Six of Hearts, I thought it was a flush, but the game judged it as four of a kind.

[Goblin]

Four of a kind is a higher tier hand than flush, and thus will be picked. That's normal poker rules. Just like how you can't play a three of a kind and say "hey I wanted that to count as a pair" or playing a straight flush and expecting it to count as a straight or flush.
This is something you have to keep in mind as you play, not a bug.