I agree there is nothing wrong with QO-100 - our investigation mostly focused on the frequency accuracy of the transponder LO to determine the source of the frequency offset that was observed, not so much on its frequency stability. Nevertheless, the measurements did show some interesting features related to stability as a nice side-effect
I have also updated my blog post to correct the (likely) incorrect hypothesis that the wiggles are caused by stationkeeping maneuvres, this is based on the excellent work by EA4GPZ and others.
Thanks Peter and your team for the great work in making a Geostationary satellite available to the amateur community!
Wouter Jan PE4WJ