So, Planet Omnia and Omnilibrary had a disagreement over licensing some time back, with one being GPLv3 and the other being MIT, and Omnilibrary forcibly making Planet Omnia incompat. That's fixed now, but Planet Omnia is still requiring exactly 4.2.2, when Omnilibrary is now 4.2.11. Beware when setting up Omnia. Manually editing the config to allow the latest version of Omnilibrary seems to work.

I don't think this is necessarily a bug, but I do know about the licensing issue they had. For some reason, Omnia still hasn't updated to allow for the newer versions, but as long as v4.2.2 of Omnilib is on the portal, it should load up just fine.

That being said, there is a reason it is listed as both Optional as well as Not Recommended on the main info page (and it may just be incompatible with Cerys anyways, so double the reason not to include it)

Planet Omnia just updated to fix this.