I don't remember who, where, or what materials were involved, but someone I was playing with a couple days ago said they'd gotten material X when we were actually on the planet for material Y, and I responded as if they were an idiot. Whoever that was, I owe them an apology.

...and got relic iron as a reward. Is that a thing? I've never seen that happen before. Three relic iron popped up on the side of the screen where the rewards show.

Yeah, you can now get mats as a reward for public events, I think it was mentioned in one the patch notes\details, and it can contain mats from other locations.

I did one on Venus and got Helium with mine.