Maybe I'm late with help.
You are completing hand with fifth 3 in this case.
Description says: Note that there are EXACTLY 4 identical copies of each kind of tiles in a deck.

Can someone please explain to me why for

1233334578999 (the 6th python test)

I am failing with this message:
'369' should equal '69'

based on my understanding of the problem 3 should be a valid solution.

1233334578999 + 3
12333334578999
123,333,345,789,99

Done. Added that info.

It's almost true (actual limit is 4000). But it has nothing to do with the moderation team, only with "power users" privileges

What does it take to get in the moderation team?

The moderation team is fairly new (just 2 months or so) so, for now, only users long known from kazk (current cw's maintainer) are in the team. It's sort of "on invitation" because currently, there is no other way.

Things have been evolving on every aspects of CW, lately (even if not that visible for regular users), so there are a lot fo things that are temporary / not decided yet / will evolve in a more or less near future.

Even more appreciation from me since you are doing this as a service. What does it take to get in the moderation team? Somewhere I saw that people with 3000+ points can approve Kata. I don't think that's true.

Do you work for CodeWars? Just curious.

nope, neither of us. Free time only x) (but I'm in the moderation team, yes)

maybe you should explain in the description how the large tests are organized. With the current explanation, there could be 4x 50x50 or even 100 of them, the user cannot know. While in fact that's neither of those situation.

There are 50 mix-sized tests and 10 fixed-sized tests. This won't help you understand timeouts, though, because the majority of time is spent on the last couple of large tests of size 50x50.

how many tests are there in total?
Will help in terms of understanding how far off we are from completing before the timeout