This question has been asked before (here is the link phonological ambiguity). In relation to this question, I came across some data in which two different syntactic structures (with the same phonological structure) are polysemous in the sense that the first is encoded in the active voice and the second is encoded in the passive voice.
Active: X dug a small well
Passive: X dug a small well
X in the active voice refers to the Agent (doer of the action), but it refers to the object in the passive (a small well). The structures in (1) are transliteration of the sentences in (2) below:
t.Rza t.anu.t 3rd.F.SG.*dig*.PRF (a small) well 'She has dug a small well.'
3rd.F.SG.dig.PRF (a small) well
'A small well has been dug.'
In the literature of Distributed Morphology, Borer (2005a, 2005b, 2013) argues that ONLY words can be polysemous, but not STRUCTURES. I am not sure of any work which considers syntactic structures polysemous in this sense of 'voice syncretism', and I am not sure about their existence in other languages too, if anyone knows more about this issue please tell me. Thank you.