The straight line about 600 m south west of your marker is a drawing error. It can't be found with an editor in the database. The border between BC and AL is the line 500 m north east of your marker, this one: https://www.openstreetmap.org/way/684908418 . It is also the south west border of the Municipality of Jasper, which lies completely inside AL. You can see the different texts written at both sides of this line when zooming in.