Are we supposed to be able to use champs already active in podium 1, also be used in podium 2, 3 and 4 as well? As in, can onslaught be used in all 4 podiums at the same time? Because it seems like it's possible, and I doubt that it's an Intended feature.

Above pic we can see the note "this champ is being used in another podium" one can assume it means we can't use this champ in a different podium, kinda like champs used in AQ can't be used in story/daily quests.
But, it seems like there's a workaround here where we simply choose a different champ first, then switch out the first champ with the one you want. And same can be done for all podiums. The dupe champs can also be used in fights to earn points which are counted towards the milestone.
An alliance mate sent me this recording here.

Sorry for the terrible gif, but had to compress it for file size limitations.
Also to end this, is it "wrong" to exploit this bug? Like can a player be banned for this, asking for a friend ofcourse