In all proceedings taken under this article, if real property or any interest therein is intended to be affected, the petitioner shall file in the clerk’s office of each county where the property is situated a notice of the pendency of such proceeding which shall set forth the general nature and object of the proceeding and a brief description of the real property in that county to be affected thereby, which notice must be filed with the petition or at any time thereafter and before any final adjudication in the proceeding. The clerk shall index such notice against the name of the alleged incompetent. The pendency of the proceeding is constructive notice from the time of so filing the notice only to a purchaser or incumbrancer of the property affected thereby from or against the alleged incompetent with respect to whom the notice is directed to be indexed. A person whose conveyance or incumbrance is subsequently executed or subsequently recorded is bound by all proceedings taken after the filing of the notice to the same extent as if he was a party to the proceeding. But this provision shall not prevent a jury in a proper proceeding, on sufficient proof, from rendering a verdict that shall overreach any conveyance or incumbrance theretofore executed by the alleged incompetent, so as to make such conveyance or incumbrance prima facie void.