metatag integration with eck

Hello, i have a project where i'm using Eck and metatag modules, the metatags doesn't seem to be saved for the entities created with eck, i don't know if its eck or metatag related, but after some digging i found that the "entity_id" is set to "null" when the function "metatag_metatags_save" is called.
so i had to use a form alter for a workaround, the steps to reproduce :

-install eck
-create an entity type
-create a bundle from it
-install metatag
-enable metatag for the entity type above
-create a node
-edit metatag values and save.

Regards.