We introduce a novel locality violation and its repair in Southeastern Sierra Zapotec: an object pronoun cannot cliticize when the subject is a lexical DP. We develop an account in which pronouns and lexical DPs interact with the same probe because they share featural content. In particular, we suggest that the Person domain extends to include non-pronominal DPs, so that all nominals are specified for a feature we call [δ] (to resonate with DP), while all and only personal pronouns are specified for [π]. This account aims to unify the locality violation with the Weak Person Case Constraint (PCC), as well as parallel constraints based on animacy, and requires a departure from Chomsky’s (2000, 2001) classical system of featural co-variation (Agree). A functional head must be able to overprobe: that is, interact with more than one goal, even if its requirements appear to be met. We introduce a probe activation model for Agree in which, after applying once, the operation can apply again, subject to certain restrictions. We compare probe activation to two other systems recently proposed to account for overprobing: Deal’s (2015, to appear) “insatiable probes” and Coon and Keine’s (2021) “feature gluttony.” Neither can account for the locality pattern in Zapotec.