https://bugs.freedesktop.org/show_bug.cgi?id=100593
--- Comment #8 from Gašper Sedej gsedej@gmail.com --- Hi.
My "shader color corruptions" bug was solved by "ppa-purge" and then again adding repository & updating.
I was not using oibaf-ppa but padoka-ppa (https://launchpad.net/~paulo-miguel-dias/+archive/ubuntu/mesa),