I don’t think it’s a bug, it’s probably due to an asset that is used for the landing challenge, being part of the A320NEO.
Base game MSFS content will have been developed based on the assumption that all players have all the standard edition content installed. I don’t know what precisely, but it most likely does need something from the A320NEO.
Is there an A320 on approach ahead of you or on the ground at the airport during this challenge?