Hofbrau Keg Coupler Help

So I recently purchased an “S” style coupler and a keg of Hofbrau Dunkel to christen it with…

…but I seem to have an issue. Lost a botle of CO2, which is a rarity for me these days. Upon closer inspection, the coupler isn’t able to rotate to the fully to seal up. You can depress the handle and it doesn’t leak beer and dispenses fine, but it’s about a 20o turn from the bumps on the coupler touching the stops on the keg.

Multiple sources list it as being an “S” type keg:

The coupler I purchased:
https://www.amazon.com/gp/product/B00FXLZHZO/ref=ppx_yo_dt_b_asin_title_o05__o00_s00?ie=UTF8&psc=1

Side rant: Do distributors save the old beer for consumers or something? I’m not going to share the “drink by” date, but suffice to say it’s well in the past for this keg…still drinkable though.

Can’t help you with the main question Phil, but thought of you and your ongoing crusade when I saw this, shared by Boak and Bailey a few days ago:

Seems the government-mandated middlemen of multiple countries share the same number or scruples…if we’re going to have to live with a three-tiered system, that middle tier needs some accountability.

Well it’s definitely leaking from the coupler/keg connection, and the beer is noticeably stale already. (Not surprising considering it’s age.)

Nobody has any ideas?