To me it seems that they (Devs) really don't know what the arena mechanics are in the first place. I'm assuming what their technical team only does are mere "translation work", and a shoddy one at that. They have to wait for the actual thing to happen and input from the players before saying "Okay guys, apparently this is how it goes..."
When Seasonal Arena was implemented weeks ago they had no clue about the "rules" (must be 6path once to claim current rank rewards, server must be 60 days to claim rewards), only when players raised hell about it that they posted those rules.
And now, yeah, they made that change to the rules AFTER HK servers had reset for March, when they saw what would actually happen. Yep, they are just hiding it. From the start they have no idea at all.