Sure, the Iron Banner has it's own set of medals that are exclusive to the iron banner and cannot be obtained in other Non-Iron Banner activities.
However, Iron Banner is a game mode type that is a part of the Crucible. Normal Crucible Medals can be earned and seen inside of any crucible match, including Iron Banner. These Crucible Medal Triumphs should not be biased to its subset game modes, when the generic crucible medals clearly display during any of the crucible games.
If this was true about Iron Banner being so removed, then no generic crucible material should be counted for Iron Banner. Things like Crucible Bounties, or ADA Crucible Threads, or normal Crucible guns, should not be obtained during the Iron Banner. We should only obtain Iron Banner weapons and armor, and Iron Banner medals, and complete Iron Banner Triumphs, and whatever else is Iron Banner exclusive.
There is no intuitiveness here to tell anyone that Crucible Medal Triumph XYZ is unobtainable in Iron Banner.
This all also assumingly applies to Trials of Osiris, and other special Crucible game types I am unaware of.