@suchcris,
The link below has the Best Offer policy for Auction style listings in it. It is under the 2 circled plus signs which are Immediately under the How to add Best Offer to your listings, header, near the top of the page.
All Best Offers that have not been accepted or have received a counter offer, will end if a bid is placed on an auction, or another member uses Buy It Now (BIN). It ha been that way since Best Offer was introduced to the site.
https://www.ebay.com/help/selling/listings/adding-best-offer-listing-using-reply-offer?id=4144
"I’ve heard another seller mentioned this when I inquired about a price on an auction, he was willing to accept but was unable to send an offer due to a bid already being placed.
Just seems very weird and counter intuitive when some sellers/buyers are willing to deal upfront!"
Since ebay started out as basically a mostly Auction site, they have always felt that Bids take precedence over BIN prices or Best offers, and both options go away when the first bid has been placed. Inquiring about a price is not the same as making an offer, if the option is not showing, and has no binding standing, in ebay's eyes.
Since most offers on an auction would probably be below what an item price might currently trending at, or even the starting bid price. It makes perfect sense that they would give precedence to the bidding process, since the higher the price, the more ebay and the seller makes from the sale. Besides most experienced bidders will wait until near the end of the auction to bid, significantly raising the price.
While a seller could end an auction with bids, by cancelling them, in order to accept an offer. Doing that would probably cause the other bidders not to want to bid on the seller's auctions again. That could hurt future sales if they mostly list items in the same general category.
Anecdotally, when Best Offer was first allowed on auctions, I tried it out on a few of my auctions, but did set the auto accept/decline feature up. Each auction had members that burned through their 5 allowed offers within hours of the auctions starting. Those offers were all ridiculously low ones, even their final "best" offer. So I never used the feature again. I also decline unsolicited offers on my auctions that have bids, and if the buyer persists with making offers, I block them.
"THERE IS NO SUCH THING AS FOOLPROOF, BECAUSE FOOLS ARE SO DARNED INGENIOUS!" (unknown)
