Pathfinders have the same default 50 view range that all scout units have. Like the M3 Scout Car, JLI, M20, Puma or the 222. Snipers have 45 default sight range because otherwise they'd be able to self spot at max distance from the get go.
Then this is definitely a bug.
Try this out.
On vilshanka, have an hmg cover the south cutoff, and get a pathfinder in green cover on near the church.
You will spot that hmg through the fog, this is intended?