What light was the Falcon 9 grid fin occulting in todays SpaceX Nusantara Satu Mission live broadcast?

I backed up the time slider on the YouTube live broadcast and snapped some screen captures, cropped with python and made a GIF below.

There is some light that blinks because it's seen through the grid fins, slowly moving.

Moon? Light on the ground? "Chaser" spacecraft's headlights?

This is seen between about T+ 00:05:39 and T+ 00:06:00.

SpaceX Nusantara Satu Mission live broadcast

Full screen:

SpaceX Nusantara Satu Mission live broadcast

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    $\begingroup$ Everybody including SpaceX calls them 'grid fin', why introduce a new term and muddy the waters? $\endgroup$ – Hobbes Feb 22 '19 at 11:42
  • $\begingroup$ @Hobbes edited. Of course everybody including me calls them grid fins. I have no idea why I added "waffle" but it's gone now. $\endgroup$ – uhoh Feb 22 '19 at 11:53
  • $\begingroup$ I suspect it is a reflection of the moon, which was nearly full and high in the South sky from the launch site. Your GIF shows it before re-entry burn, and it also reappears (better view) just after that burn, at T+00:06:47. $\endgroup$ – amI Jun 1 '19 at 4:30
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    $\begingroup$ It would have to be reflected by the Atlantic ocean. There are also clouds or land visible between the two visible grid fins. I don't know the trajectory or location of the landing barge, OCISLY -- was there a boost-back burn? (It had the highest entry heat load to date). The angles don't make sense to me, but it looks like the Moon. $\endgroup$ – amI Jun 1 '19 at 5:31
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    $\begingroup$ You are right (except Feb, not June) -- I goofed the UTC offset. On East horizon makes sense. Maybe the smaller light just to the left is the weaker reflection. Thanks for clearing this up. $\endgroup$ – amI Jun 1 '19 at 6:19

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