I typically play a hunter so I have only noticed it on this character when the leather working guide is active. When I have the cooking profession open and making food – If I gain a rank the frame immediately switches to the Leather working frame, everytime.
Found this out by disabling all of my addon’s, then putting them back one by one. When I got to the Dugi Guide it happened. When I looked at what guides I had opened I noticed the Classic Leather Working guide. After I cleared this guide I was able to Cook without it switching.