Why are there grey bubbles appearing in my iphone message app?

[iMore Question]

These bubbles are similar to the initials filled bubbles or photo id bubbles at the beginning of a message, however these bubbles are empty or devoid of message. They are just grey circles with no initials or photos.Sometimes there are three in sequence, then a space or two, then some more. I can hit edit and check these empty messages then delete them as i would a regular message that i have read, but some more empty message bubbles appear. They're annoying!!