Yerushalmi Gittin 8:6 ירושלמי גיטין ח׳:ו׳

MISHNAH: If somebody married his sister-in-law while her co-wife went and married somebody else, if the sister-in-law turns out to be a she-ram, the co-wife shall be divorced from both of them and all the aforementioned consequences apply to her⁷⁴A “she-ram” is an infertile woman lacking secondary sex characteristics. Her marriage is considered non-existent by biblical standards. It is the basic tenet of the House of Hillel that if a man dies without issue and any of his wives is forbidden to any of his brothers, all of his wives are forbidden to all the brothers and are free to marry outside the family without further ceremony (cf. Mishnah Yebamot 1:1). If the relative turns out to be a she-ram, who cannot be married, the release of the other wives turns out to have been erroneous and their new marriages incestuous for those who hold that the outside marriage of a candidate for levirate marriage is incestuous (which is an opinion of R. Aqiba rejected by his successors.).

HALAKHAH: “If somebody married his sister-in-law,” etc.⁷⁵This text is Yebamot 10:5, Notes 116–121. If she should not have married but entered levirate, this is the case of a sister-in-law who married without ḥalîṣah. Rebbi Jeremiah said, this man performs ḥalīṣah, the other one keeps her. Rebbi Jehudah ben Pazi in the name of Rebbi Joḥanan: She must leave. Rebbi Yose asked Rebbi Phineas, how does the rabbi hold? He said, with Rebbi Jeremiah. He said to him, change your mind, for otherwise I shall publicly call you a rebellious Elder. Rebbi Zevidah said, a baraita supports Rebbi Joḥanan: “She must leave both of them and the thirteen items apply to her, following Rebbi Meïr who said it in the name of Rebbi Aqibah. But the Sages say, there is no bastard from a sister-in-law.” Therefore she must leave.