Does the stipulation in a settlement of a sexual assault case apply to a prior conviction that was later vacated by a writ of habeas corpus?

Stermer suggests that the stipulation was based on the fact of the conviction and its legal consequences, which fact and law were deemed never to have existed by virtue of the vacation of that conviction. At the time of the stipulation, the conviction existed. That it was later vacated by a writ of habeas corpus (see People v. Sumstine (1984) 36 Cal.3d 909, 920, 206 Cal.Rptr. 707, 687 P.2d 904 ["judgment [of conviction] ceases to exist for all purposes"]) does not legally create a mistake as to its existence at the time of the settlement, especially as the parties stipulated with the knowledge that the petition for writ of habeas corpus was pending and might lead to the vacation of the conviction.