Part magic invisible faces

Sometimes a part magicly turns faces invisible.

Breaks mates if they use this suddenly invisible face.

Not transparent, not display change, just random invisible faces.

Ctrl Q is the only way to get faces back.

did a Rollback Quadro driver from 376 to approved 354 yesterday cause i thought this may be the cause.

Example happened today.

Suddenly after all morning with assem open.

Magic invisible face appeared

open part

Ctrl Q rebuild fixed

Has anyone else seen behavior like this?

Solidworks 2015 sp5, Nvidia Quadro K2000

SolidworksParts And Features