Garageband for iOS tells me I am missing sound pack(s) but not which ones

I have been using my iPad a bit for making music with GarageBand. I save my material to iCloud. Today I wanted to open one of my tunes on my iPhone, instead (I didn't have the iPad with me), to play for someone. When I clicked on the file, it said, "Missing Sound - This song is missing sound pack(s) that were originally downloaded from the GarageBand Sound Library. You will need to manually download each missing item to make this song complete." The only response options are Sound Library, and Cancel.

Going into the Sound Library from here doesn't highlight anything or show me what I might be missing. Similarly, I can't go ahead and open the specific song anyway to discover which tracks might be missing their associated sound libraries.

Is this normal? How would one identify which libraries I'm missing? I have a lot of them on the iPad, I have no idea which ones I'm using. I don't want to have to download them all here, but I also don't want to have to just give up and move on.