I go with lens obstruction.
Now, what caused it is curious, yet, as it does not appear to have any clearly defined margin, I highly doubt this is a potential doom scenario.
On the other hand, this all depends on the nature of what caused this 'veiling' effect, which does not appear to be anywhere near the Sun.
BTW: Did anyone see the recent Scifi movie "The End of the World?"
It was extremely funny. As doom movie go, this one had a very GLP community sort of atmosphere to it.
The entire script played like a thread, as people with absolutely no advanced background in solutions wound up saving the world nonetheless, hugely by just recalling scenes from doom movies they were huge
It was brilliant, even though you had to overlook certain anomalies.
That's what the video reminded me of...[almost] an approaching wave, as in the movie.