I'm attempting to use the new Membership API to update membership records.  We have a class of members whose memberships do not expire, but whose membership records were erroneously given an expiration date.

When I use the API to update the membership expiration date to NULL, I throw a validation error.

PUT /people/:person_id/memberships

{
  "membership" : {
    "name" : "Standard"
    , "status" : "active"
    , "expires_on" : null
  }
}

Any thoughts on how to fix?  I'm considering just setting the expiration date 100 years in the future, but that could upset queries for members without expiration dates.