https://bugs.freedesktop.org/show_bug.cgi?id=104490
--- Comment #2 from Michel Dänzer michel@daenzer.net --- (In reply to Sebastian Parborg from comment #0)
[...] there seems to be some kind of cached behaviour (not the mesa shader cache as I removed the directory [...]
Which directory exactly did you remove? Have you tried setting the environment variable MESA_GLSL_CACHE_DISABLE=true to see if that avoids the problem?