Missing sizes after Regen. Thumbnails

I am using rtMedia with Buddypress and Woocommerce. When I Regenerate my Thumbnails (with Regen Thumbnails) I lose all of my sizes except for the rtMedia sizes. If I deactivate the rtMedia plugin and regenerate, I get all my sizes updated.

It may be a conflict with my theme or another plugin but, for now I can work around this issue. I just wanted to bring it to your attention.

Thanks.

By default the media associated with rtMedia does not create additional sizes except for the rtMedia sizes and the media not associated with rtMedia creates sizes other than rtMedia sizes.
This is a default behavior.