I’ve tracked down the bug!
See FS2020 OMDB below, it has the 3 terminal buildings that are missing from 2024.
The 2024 Library says the FS2020 Premium Deluxe airports are streamed, which includes OMDB.
It’s a coding bug.
Speculation: It looks like 2024 is NOT streaming the OMDB terminal buildings, because it thinks they are already streamed in the 2020 airport. There maybe duplicated IDs in 2020 and 2024 terminals causing the problem, but in fact they are different and the 2024 code would not load old data models anyway.
The scenery devs need to dive into the data and find the clashes between old and new terminals, that are causing 2024 to not stream the entire airport.
There is a similar problem with Gatwick EGKK. I know my description is complex, but the devs will understand the problem.
Did Asobo promise to upgrade 2020 airports as well as planes?