I get the message "Unable to smelt Metal-catalyst carrier. It might have something to do with that product having 23 different recipes that can make it, all of which have multiple inputs and outputs (that are mostly gases) expect for one...and that one is 5 iron plates = 1 Metal-catalyst carrier. I have the Experimental checkbox unchecked. I can supply a savegame but not sure how to get it to you. I frequent the Factorio Discord voice channels as "rmm".

Surprisingly enough, the issue was actually a self-imposed one. For some reason, the entire subgroup for those catalysts (everything in the same row of the crafting menu as the metal catalyst carriers) was on the no_recycle list. I don't actually remember when or why I added them there, but it seemed safe to remove them.

Should be fixed as of v8.2.17