Why is one text document displayed and the other is not?

I have 3 plain text ( .txt) documents in a directory within the assets directory. Two of the documents will display thier contents in the inspector when I select them, while the 3rd will not.
Mechanically all 3 documents are identical as far as anything I can examin.
Of the two that will display thier contents, one is 1kb in size while the other is 4kb in size. The document that will not display is 2 kb in size.
Based on that observation it can not be a size or character limit restrictions.

did u try to reimport ?
did u put it in streamingAsset Folder?
did u change the file encode ?