I think the avatar issue might arise when someone tries to change their avatar. My pre-alpha3 avatar was fine until I tried to change it post-alpha3. Now it's gone.
Two questions:
1) do you know which directory the post-alpha3 avatars should be in and
2) Is the image uploaded through the CB Profile "Upload My Picture" still used as the phpbb avatar picture (I'm not aware of any other place in the profile section to upload any other pictures that could be used as an avatar).
Off the top of my head not sure where the directory is... it should be the default CB (or phpbb) directory...
In Alpha 3 the avatar sync should be disabled as there are some things I want to tweak in that area that I don't have the time to currently change...
I will check into the avatar sync issues... also we probably should post Alpha 3 issues on the cbconnector.com site under the alpha 3 area so they can be organized together...