SEBLOD appears to be miscalculating certain permissions in content types.
I have created a new group which has been given permission to create objects in all tiers of the ACL structure (Joomla general configuration, Article Manger and Seblod's general options), Nevertheless, the permissions setting at the content type level keeps showing a conflict. Because of this, I have been unable to switch Create to Allowed.
After duplicating the content type where permissions were miscalculated, the new clone is getting then right. This does not solve the problem in itself, but provides a vaible workaround.
Had a similar issue and resolved it by creating brand new user groups and setting permissions for them in each content type (as in my case the permissions vary by content type). Then I deleted the old ones.