Perfect Circle in the Night Sky a Puzzle

We initially dismissed this one as a lens effect, but that’s not what it is. There appears to have been a circular object in the night sky over Galveston in late June. It ‘silently crossed the night sky’ according to witnesses. Do we have a drone that could do this? Certainly nothing even close to being declassified. This is a genuine unknown. (But look closely, it’s hard to see in this video.)