VERTICAL feather edge cladding...

[selfbuildrookie]

I'm currently working on a project where the architect has specified vertical feather edge cladding (oak) for the exterior of a timber frame extension... the contractor and the client are unsure of using this, and their reasons seem pretty solid: water ingress, unable to fix insect membrane, etc etc. It seems that the reason we can find no installed examples of this is because it's a Bad Idea, but I just wanted to check in with the hive mind as to whether I'm missing something important and this is a valid concept - or indeed if everyone bar the architect is correct, and this sort of cladding just shouldn't be installed vertically?