Colin Tim Barndt

Confirmed for 1.12: 17w17b

Thanks.
I did not notice that it has already been reportet.

Yes:

1: /tp @a[score_join_min=1] x y z
2: /gamemode 2 @a[score_join_min=1]
3: /scoreboard players set * join 0

Strange..
I'll try to add my Server folder. Maybe this could help.