I'm confused. I booked this as part of a multi-segment itinerary on UA (OS for intra-EU flights). LHR-VIE says I have to pay for any seat assignment, which implies an Economy Light Fare, but on the OS site, it's showing me one checked bag as my allowance.

This doesn't seem to be a legit combination, per OS's own website. Can I reasonably expect that I will get one free checked bag, plus a second one on account of Star Gold status? Or given that I can't select a seat without paying, is it really an Economy Light fare and I'll have to pay for a checked bag? Travelling with others who are on an OS purchased Economy Light fare, so me having a checked bag allowance is material.

Could this be because it's booked on a US-LHR-VIE ticket (although there is a several day gap between the EWR-LHR and LHR-VIE legs)? Interestingly, my return, which has me VIE-LHR-US with a less than 24 hour connection is showing up as 2 free checked bags, but that one I'm clearly attributing to the through connection.