I'm posting this issue, because I have find very little information about this message:
The core RDF module is known to cause validation problems for Open Graph meta tags. Unless it is actually needed for the site, it may be worthwhile to disable the RDF module to avoid any possible problems for the Open Graph integration.
... so, I'm wondering what kind of problem I'm risking!
Actually, I need the RDF module for Schema.org, and I think that many people which are interested to OpenGraph may also want Schema.org features.
Could it be possible to have some indication about the issue and also, if and when it could be fixed?
Thanks for help.