It look like NationBuilder's auto-districting feature is using outdated provincial electoral district boundaries for British Columbia. BC's provincial ridings were redefined in 2015, and supporters are being assigned to districts that no longer exist. There's a provincial election coming up in May 2017, and campaign planning is happening now. Any timeline on when NationBuilder will be updating their auto-districting feature to reflect BC's new electoral district boundaries?
Update 11/08 -
"The BC electoral districts have been updated to reflect the new boundaries! To refresh your nation with the updates, you'll need to turn auto-districting off, save, and back on. You can do this by going to Settings > Political > Settings and check the box next to "Automatically update Federal & Provincial ridings when an address changes".
More about auto-districting here: http://nationbuilder.com/auto_districting"
Please see Victoria's comment below - we will update let you know when this is complete!