Same thing for me, I have to download the A300 twice for having Inimanager display the latest update correctly.
Moreover, Inimanager downloads each time the full version of A300 (1.9 Gb) !!!
On the contrary, everything is correct for A310, the update is correctly displayed by Inimanager the first time and only the modified files are downloaded.
(Xplane was not running, Inimanager version 1.04)