Belgium (Liège): silver 2-escalin of Johann Theodor of Bavaria, 1753 (contemporary counterfeit?) KM-161, silver. Numista-33459. Silver, 28.2 mm, 7.44 g. Struck under the authority of Johann Theodor of Bavaria, Prince-Bishop of Liège. Ex-Jean Elsen et ses Fils Auction #142, Lot #938 (part of), 14 September 2019. I sold this coin on eBay in the summer of 2020, and the buyer returned it, saying it was a counterfeit, with the apparent implication that it was some kind of modern counterfeit. I didn't question his assumptions and promptly refunded his money, though I very firmly disagree with the notion that this coin is any kind of modern fake. The coin looks consistent with pictures I've seen of others of this somewhat crudely-struck type, as best I can tell, but admittedly I do not know for certain. It is entirely possible the would-be eBay buyer saw something I do not see. It does seem to be slightly underweight based on the specs given on Numista. I acquired it as a part of Lot #938 in the Jean Elsen et ses Fils Auction #142, on 14 September 2019, so it came directly from Belgium as part of a large lot of older coins and tokens of Liège. If it is in fact counterfeit, I am much more likely to believe it could be a contemporary counterfeit from the 1700s. But I'm not sure I buy that theory, either. Really, I don't know. The coin looks fine to me. But I could be wrong.
I've dealt with Jean Elsen for over 20 years. I really doubt that he would sell a counterfeit coin, even in a group lot. More than likely your Ebay buyer returned it because of his/her financial situation. I agree with @Chris B , that if it is fake, it's a convincing one.
I am going to preface this by saying that Belgian coinage (pre-unified state, as well as Kingdom) is my field of personal collecting interest, so I have seen / handled quite a few of these over the years. This being said, there are MANY die varieties of these (many not listed), and that there also exist extremely sophisticated contemporary forgeries. Something looks off to me in the Lion (looks a little too emaciated), the rims (too indistinct / flat, although it would simply have been shaved a bit), and that the overall style of the arms is not quite as good / crisp (if that makes any sense) as what I would expect. So, IMO, it is either a very good contemporary counterfeit (collectible in its own right), or alternatively a piece from a junior engraver which has been shaved at some point in its life. I think the only way to really know will be by putting it under an XRF to see the purity.
I concur. This pretty much echoes my (admittedly uninformed) thought process on the matter. If it's a contemporary counterfeit from the 1700s, that's not all bad news, because as you say, then it is still collectible in its own right. Personally, whether it's a crude variety of an official strike, or a contemporary counterfeit, it's over 200 years old in either case. I'm nearly certain it is not a modern fake of any kind. It's interesting, regardless. Since it came from a large bulk lot (which I did very well on, thank you very much), even if one were to consider it as the lone "dud" from that lot, I have no cause for complaint. I think did just fine, for the money I paid for it, as a one fifty-ninth portion of that source lot. A relatively trifling sum when you average it out.