I have the exact same problem just west of CYVR.
Checking ORBX!VECTOR_CVX leaves a faint outline of an extended river/coast. Checking ORBX!VECTOR_EXX fills in the outline with land textures. Google satellite view is misleading, the area looks like regular ocean except at low tide.
Unchecking "Wetlands" in FTX Central doesn't make a difference.
Running P3Dv4 with ORBX Global BASE, Vector, and OpenLC NA.