eBay replied to my inquiry about this auction. Here is their reply:

Hello Robert,

Thank you for taking the time to contact us with this information. I
understand how this situation could be of some concern.

I have reviewed the information that you have sent in regarding shill
bidding and at this point find that we do not have enough evidence to
show that the member has violated any eBay rules.

Although you are correct regarding the auction, we just do not show any
correlation between the bidders or the seller.

Again, thank you for writing to us with this information.

Regards,

Stewart
SafeHarbor Investigations Team