Perhaps you have different tag versions (APE, Id3v1, id3v2.3) that are conflicting?

You Ingur album doesn't work for me, but from what you say I think this is much simpler than you are making out.  It seems that in one case the text is being displayed with title or camel case, and in another forced to all lower case.  This will be a display/text rendering property rather than anything in the metadata.

However, what you say about FB2K reading the metadata from the files is not correct – FB2K builds a cache of metadata associated with the filename, so if you replace the file (outside FB2K) it won't pick up the new file's metadata unless you refresh the cache (I don't know how to do that in mobile FB2K).

You Ingur album doesn't work for me, but from what you say I think this is much simpler than you are making out.  It seems that in one case the text is being displayed with title or camel case, and in another forced to all lower case.  This will be a display/text rendering property rather than anything in the metadata.

However, what you say about FB2K reading the metadata from the files is not correct – FB2K builds a cache of metadata associated with the filename, so if you replace the file (outside FB2K) it won't pick up the new file's metadata unless you refresh the cache (I don't know how to do that in mobile FB2K).

Actually it seems the second link i sent is only one image. I can't figure out why the first link in my topic post isn't working for you since I can still open it when I am logged out of imgur.

If your first explanation is true, then I am not sure why only this small handful of albums would be affected by some text formatting overriding the metadata

Agreed, in which case were left with caching.  See whether editing a tag within FB2K alters it – edits performed using FB2K should also update the cache.

It's not a caching issue. The player/skin capitalizes the tags if they are in all lowercase.

It's not a caching issue. The player/skin capitalizes the tags if they are in all lowercase.

I was wrong, it's not a formatting issue. Media Library shows the tag contents using the capitalization it learned when it first saw that particular string. If mobile foobar2000 has seen album name "The Most Wonderfulest Thing" before seeing "the most wonderfulest thing" the tag based browser will show the capitalized variant. It seems Media Library only stores strings once and ignores case.

So for media library you can't have different spelling for same names.
If you are certain you don't have differently spelled tags in your library folders and wish to force the titles to "correct" case, just wipe foobar2000 data in phone settings and let it reindex libraries. That will refresh Media Library caches. But as you have already done this in a slower way by uninstalling and reinstalling, it would appear that you do have different spelling somewhere in your library.

Load the Album (Track) in foobar2000, set the tags, then right-click > Tagging > MP3 tag type...

If you are certain you don't have differently spelled tags in your library folders and wish to force the titles to "correct" case, just wipe foobar2000 data in phone settings and let it reindex libraries. That will refresh Media Library caches. But as you have already done this in a slower way by uninstalling and reinstalling, it would appear that you do have different spelling somewhere in your library.

That's exactly what I mean. It will wipe all foobar2000 configuration data and you'll get a fresh start on next launch. I did that many times when testing the capitalization behavior.