Thanks to everyone so far for your answers and insight. I called LO again - English is definitely not their strong suit, but I got out of the agent this time that they are seeing a ticket number for my reservation, but she was confused by the reservation.
My overall trip is CLT-ORD-WAW-BUD; PRG-FRA-IAD-CLT. But when I log into either the LO or LH websites, the only segments that appear are ORD-WAW-BUD; PRG-FRA-IAD...so essentially, the UA flight on the front end, and the US flight on the back end aren't showing.
I feel like I've seen this type of thing before, so I wasn't particularly worried - but just wanted to solicit a few opinions here as well. It sounds like, from the LO agent, that the e-ticket is there for the whole trip, even though she was only seeing the middle segments (the LO/LH segments). So given that, I think I'm okay, but am I missing something?