No, I don’t think the All caps is a bug.
My guess it that Josh may have left one of the characters in the font on the all caps setting. This setting is saved per character, not per layer.
Double click and highlight all of the text and make sure this setting is not turned on. See the screenshot showing where to find the setting. You may have to select one character at a time and see if it is toggled on for just a single character.
Worst case, just make a new text layer and it will probably fix it. Just make sure to set the text to point text mode, not paragraph text mode.