On the nvidia forums it sounds like the FE cards aren't being direct replaced by RMA anymore and are being 'repaired' instead which tells me they are receiving way more cards then 'normal'. As to what the 'repair' is we have no idea at this time. I believe nvidia 100% knows what the issue is at this point but are keeping things hush hoping the problem eventually fades away given enough RMA's.
In that case it'd be useful if people took good pictures of their card before sending them in to see if any mods are visible or parts are replaced.