Until today I was on the BETA 2.0 of "Pillars of Eternity" but after bought the extension and installed the new files (about 2gb) the game version is now 1.0.5.0582. I checked the PoE "cache files" on steam and there are no problem. I checked to go back to the normal game version (without the 2.0 BETA files) and steam is now currently in downloading 4gb of new files. I Think there are a problem with this files update.. and I hope I will solve the situation !
Otherwise, congratulations for the "White March" release. I hope there will be many more !