If Membership End Date is NULL, getMembershipStatusByDate fails to give right status

So, with my tests, I've been adding a user to a membership that is an organizational membership using Relationships to apply the memberships to users.

What happens is the relationship has no end date, and the membership is a life time membership. going into CRM_Member_BAO_MembershipStatus::getMembershipStatusByDate() $endDate is NULL.

When it goes through customFormat... it then becomes 00000. This means several of the calculations for dates actually turns into something based off of 1999-31-12 (2000-02-29 in the case of New).