DiParapassPass: In a diparapassive structure (two nouns + passive verb form derived from an intransitive verb), the agent (the “additional noun”, marking the causer of the event) is treated identically to the agent in an equivalent passive construction.
(1) əj ʌat-nə qantəɣ jɔ̄ɣ ʎaʎ-nə jowt-at.
one time-loc Khanty people army-loc arrive-pst.pass.3pl
‘Once an army arrived in the land of the Khanty people.’ (Csepregi 2011: 11.)
(2) ʌüw toɣəʌ-nə pūn-nə änm-i.
he/she feather-loc hair-loc grow-pst.pass.3sg
‘Its feather-hair grew out.’ (Csepregi 2011: 12.)
In Surgut Khanty, intransitive verbs can appear in passive constructions, too. In these cases, the agent is marked by the locative, just like in the real passive construction. The other nominal of the construction, which would have an oblique case marker or a postposition in active sentences, is the patient of the passive construction, and thus appeares in the nominative case.