And I double checked and have the LG panel in mine.
It could be a bad batch that some are suffering from. I have a Thinkpad with a 12.5" IPS panel, and there were issues with some people having ghosting too. I never could reproduce it, and it was the same panel. Lenovo eventually acknowledged it and replaced the panels for the affected users. --
Good luck to those with the problem getting Apple to admit anything. Of course this is the Tim Cook era...things may be different now. Reading more of the Apple Support thread shows those with ghosting are able to have them replaced by via AppleCare contrary to the article author's experience. But if it is just replaced without another LG panel then what...back you go. The only bright spot is that each repair is under its own warranty so the panel replacement will be covered for 12 months whether the rest of the unit is still covered or not.