Weird bars and more have been noted before. http://forums.androidcentral.com/htc-one-m8/382408-weird-icon-status-bar-when-sending-text.html
In short, SMS text messaging has been changing over time to the point that I'm seeing a lot of bars, indicators and even the weather show up in the message app.
What's common to all of them is NO DOCUMENTATION. Long ago we could open the product manual. Then it was a file or doc on the system. Today they don't bother writing it at all.
I noticed a random gray bar with a timer pop up in my text message response bar! What is it?? How do I get rid of it?? Some type of spyware? I could type but my words would go behind it and the timer never started