Pulled my filter cover off and drained it because my dash gauge also showed all bars lit. Thought it might take care of it like the OP did. While I was doing this I took a pic of my filter an it looked like it had shiny bits in the pic. I removed it and put a new one on because I wanted to see what it was. Ended up it was just the flash making the oil sparkle. I cut open the old filter and this the only thing (besides some dirt) I found in it.
Oh and my dash gauge still has all bars lit.