In Preskar Estate v Wagner 20023 BCSC 80 a BC court found that a joint tenancy with a right of survivorship had been severed so as to become a tenancy in common by reason of the joint owners acrimonious conduct to each other that was inconsistent with joint tenancy unity.
In Preskar an unmarried couple who own the property in joint tenancy had acrimonious family litigation for many years, starting in 2007 that was never resolved. The joint tenancy was never severed and when Mr. Preskar his estate died, his interest in the joint tenancy property immediately went to his partner by right of survivorship.
The estate successfully sued arguing that there acrimonious course of conduct showed that their “notional” unity of ownership under a joint tenancy had been abandoned, and thus the joint tenancy had been severed and a tenancy in common created many years before his death in 2020.
This meant that the half interest of the deceased would go to his estate rather than to the former joint tenant by right of survivorhip.
The BC court adopted the reasoning of the Ontario Court of Appeal as follows:
Hansen Estate v. Hansen, 2012 ONCA 112 which states as follows at para. 39:
 While the determination under the course of dealing test is an inherently fact-specific assessment, the underlying rationale for rule 3 is that it is a means of ensuring that a right of survivorship does not operate unfairly in favour of one owner (or owners) where the co-owners have shown, through their conduct, a common intention to no longer treat their respective shares in the proper as indivisible, unified whole. For example, in the context of negotiations between spouses who are in the midst of a marriage breakdown, even failed or uncompleted negotiations can lead to severance because “the negotiation of shares and separate interests represents an attitude that shows that the notional unity of ownership under a joint tenancy has been abandoned” . . .