Thanks for the kind words, and fascinating information.
Yes, it is reassuring to hear someone has seen something of the same nature. Even more so, when it is clear that person really knows their stuff.

I'm having fun, (if not success) trying to track down the culprit satellite.
I have learned that when GEO sats expend all their station keeping propellant, they begin to drift quite far, north, then south of the equator, in a continuous figure eight pattern.

Using this 3D Java App I tried to visually spot a likely candidate. When you maximize the 3D view, you can pan, drag, and zoom to see all the GEO Sats. Clicking on one will produce orbital data.
Kind of a crude way to go about it, but it's a start.

GOES-3 does line up nicely in the 3D view

Thank you again, and I will check out the article in Sky and Telescope.