Originally Posted by
findark
As long as (a) the OS PNR is in order and Austrian can confirm this, and (b) there isn't a duplicate Economy/Business pair of segments on the UA end, you should be good to fly.
How can one ever be completely sure in these post-Saudi days though?
Having personally experienced what happens when a ticket isn't synced correctly (albeit on OAL), I'd try a few different agents having a look at it before going to the airport.
@OP these red messages tend to clear after a few days. I'd only be concerned if they stick around for longer than a week. You're right, however, to never trust an agent saying "there's nothing to worry about". That agent won't be at the check-in desk when the system refuses to print your BP.