I've also had this issue today. This is the first time I have loaded the A340-600 with the current nav database. The navdata had apparently updated to the latest AIRAC as expected, but the only way I can get the flight plan to upload is if I select "IGNORE AIRAC/AC TYPE MISMATCH".
Looking more closely at the MCDU I noticed the end date for the AIRAC was incorrect. It shows 16MAY-13MAY, not 16MAY-13JUN, and the database number is one cycle out too (2604 not 2605). See screenshot. Could this be why the flightplan is not accepted?
Is there a way to force the database to re-download?
Edit: looking at the navdata folder I don't think 2605 has been installed, at least not properly. No new files in May or June, it looks like 2604 is installed.
By
kevinh ·