There are multiple reports of AS lounge agents denying lounge access on economy tickets to non-AA/AS OWS/OWE, just politely remind them in this case that you are permitted and have the AS webpage with the info to hand.

https://www.alaskaair.com/content/ai...cies-and-rules (listed under the FAQs section lower down on the page, it's the 4th question there)

If they still don't budge, then ensure you email AS Customer Relations. Even though it's been almost a year since AS joined OW, the memo hasn't yet reached all the staff (or if it has, they just aren't aware of the rules properly!). Hopefully as more of us non-AA/AS OW status holders visit the USA and use them more, the more used to it they'll be! AA is a pretty well-oiled machine with this now, promptly granting access with a quick "Are you Sapphire or Emerald?" question each time! Shame AA's systems still don't just pull this info up automatically despite it being coded into the boarding pass itself!

Happy travels. Hopefully you won't have any long waiting lists that AS lounges have been known to have!