So it will show up like. LEADER_IRA TXT_KEY_CIV_AMC_DESC when you go to choose the Civ.
When you see TXT_KEY entries like that, the usual reason is that there's duplication somewhere. You see, the game can only handle having one definition for each key, so if you've got something like TXT_KEY_CITY_NEW_YORK, but the game already has a key of that name for the American civ, then the mod will break. Specifically, it'll
ignore the entire contents of the file in which the duplicate entry appears, which, depending on how you've structured your mod, could either be relatively minor or completely game-breaking.
This comes up all the time with custom civs, especially for people with many DLCs, because the chances of your custom civ's city names overlapping with an existing civ become very high if you're not careful. The usual way to prevent this is to add some unique modifier to your mod's text keys. Something like TXT_KEY_CITY_SPATZ_NEW_YORK, to ensure that no other mod would ever conflict even if it had the same city name. (There's no uniqueness requirement for the keys' VALUES, so you can have two cities named "New York" without a conflict, even if they used two different keys to get to that point.)
However, if you're seeing something like "LEADER_IRA", with no TXT_KEY before it, then that's a totally different issue, and probably means you screwed up something in your XML. All text keys MUST start with "TXT_KEY_", no exceptions, and a Type variable (the only things that'll have names like "LEADER_IRA") should never be visible to the player. But figuring out this would require being able to see your actual code, or at the very least see your logfiles. (You DID turn on logging, didn't you? That's the very first thing you should be checking when you have an issue, before coming to this board.)