The variant is zonatcha vs. yonatcha and, as I've laid out several times in the past, ikka deAmrei means a variant manuscript. There was a distinction here between זונתך, "your harlot," which begins with a zayin on the one hand, and יונתך, "your dove," on the other.רב יוסף בריה דרבא שדריה אבוהי לבי רב לקמיה דרב יוסף פסקו ליה שית שני כי הוה תלת שני מטא מעלי יומא דכפורי אמר איזיל ואיחזינהו לאינשי ביתי שמע אבוהי שקל מנא ונפק לאפיה אמר ליה זונתך נזכרת איכא דאמרי אמר ליה יונתך נזכרת איטרוד לא מר איפסיק ולא מר איפסיק:R. Joseph the son of Raba [was] sent [by] his father to the academy under R. Joseph. and they arranged for him [to stay there for] six years. Having been there three years and the eve of the Day of Atonement approaching. he said, 'I would go and see my family'. When his father heard [of his premature arrival] he took up a weapon and went out to meet him. 'You have remembered', he said to him, 'your mistress!' Another version: He said to him, 'You have remembered your dove!' They got involved in a quarrel and neither the one nor the other ate of the last meal before the fast.
I believe, in this instance, that the clear winner is זונתך. After all, they got involved in a quarrel and forgot to eat the seuda hamafseket. This would clearly result from Rava calling his daughter-in-law a harlot to her husband's face. Calling her a dove, which is a sign of affection, would not cause such a quarrel, and is wholly out of line with him taking up a weapon when going out to meet him.
Indeed, there is the principle of lectio difficilior we might apply here. It is more likely for a scribe to emend the text towards less harsh terms than harsher terms, because of the difficulty of accepting that Rava used such a slur against an innocent woman. Of course it is a scribal error, but perhaps a scribal error in one direction would be caught because the scribe would jump back at what he just wrote.
But this is not the only time that this particular word has generated variants. As Soncino notes in a footnote on the word zonatcha:
Lit., 'your harlot'. Var. lec. 'thy mate', 'thy beloved'.That is, there is a variant girsa with a gimel in place of the nun, such that it reads zugatcha, זוגתך. If so, then both terms in the ikka deAmrei pair are terms of endearment. I doubt this would be the original girsa because what spark would there be for the savora to note the girsological variant? -- since they have the same basic implication. And of course, we have the mismatch between the tone of the rest of the narrative and this term of endearment.
No, what we have instead are two tiers of girsological variant. The first was fairly early, and was "your harlot" vs. "your dove." The true original was "your harlot," but the difficulty of Rava saying such a thing helped along the variant "your dove." Then, the same thing happened again, from the same word, "your harlot." This time, instead of changing the zayin to a yud, a scribe changed the nun to a gimel. Thus, it became "your mate."