In Fitzpatrick v. Kent, 458 P.3d 943 (Idaho 2020), an owner of of two adjacent lots recorded a grant of an appurtenant easement over the servient estate for maintenance of a pond and irrigation system to benefit the dominant lot. The Idaho Supreme Court held that this purported grant of an easement was invalid since one cannot create an easement in one's own property. So when the owner sold the servient estate, it was not subject to the easement because the deed given to the servient estate owner did not itself reserve the easement. It also did not matter that the servient estate owner was aware of the easement and impliedly agreed to it.
The opinion places formality over substance, but is based on an old property law rule whose purpose is to ensure that easements (and covenants) are created at the same moment that the owner parts company with the land that is to be restricted or burdened. For the same reason, Prof Dale Whitman cautions that developers who record declarations should make sure that the first deed sold contains within it a reference to the declaration to insure that courts view the deed as incorporating the restrictions defined in the declaration. And it is better practice to have every deed subject to the declaration also to mention the declaration so that it is crystal clear that the property is covered by the declaration. Some courts, however, may find the subsequent properties burdened by the declaration if the buyers would have been on record notice of the declaration at the time they purchased their lots.