There's an object with OneToOne association (the owning side).
When trying to hydrate it using partial query NOTICE is outputted.
Notice: undefined index [_FK column_name of OneToOne assoc_] in UnitOfWork on line: 1773
Probably, the reason is in the way Query calls hydrator's iterate method (with no hints passed to it). Therefore the UnitOfWork object is not affected by HINT_FORCE_PARTIAL_LOAD hint set to the query object.
pass _hints array to a hydrator::iterate method when calling it from an AbstractQuery::iterate method.
Am I right?