Sean,
Yup, sorry, got a little behind on answers.. we're catching up quickly though. Never like making our users wait more than 24 hours.
I have a few questions about the avatar resizing thing. The size40 isn't a default for Kunena, that I know of. Do you have something configured differently than the defaults for avatars? If so, can you let us know what and how you have it configured? Generally, regardless of the size, what Kunena does (we've looked through their code) is check the sizeXXX folder for the user's avatar.. if it doesn't exist, it's created on the fly. So, even if you have a different configuration, it should be creating that size automatically.
As for the recommendation module.. I'm not sure why or how it would be pulling the user's avatar at all. Can you point me to the page that this error is occurring on, or any other info?
Finally, for the image, that's pulled from Facebook based on the page and what it thinks is best (for now). With 3.2 we'll have some options for telling Facebook what avatar to use per page. Those changes will be retroactive, so wonky images now can be corrected later, just so you know.
Hope that helps, and definitely give us more info about your avatar settings in Kunena!