White message icon on text messages

Hey there BKlookingforanswers, 

Thanks for the photo! Tapping this icon will mark the current message or thread as unread. Tapping the similar icon with the check mark will mark the message or thread as read.  

Have a good one!

Hello BKlookingforanswers,

To help us get a better understanding of the issue, we’d like to ask a few questions.

1. Does this appear on all Messages, or only certain messages, or messages from certain contacts?
2. Is this happening in the Apple Messages app, or another application?
3. When did you first notice the icon? Were any changes made to your device before it appeared? If so, what changes were made?

The above details will help us determine how to proceed.

Please also check out this link, as it has some good information about Messages, and may be helpful: Use Messages on your iPhone or iPad

Thanks!