Seems there are a lot of engineering bugs since patch, and as an engineer i couldn't be happier! One more to add to the growing list is with the Mind Amplification Dish. No it's not the fun with mc's. Since 4.0.1, engineering tinkers are allowed to stack with normal enchants. Specifically, the tinkers that DO NOT add stats now stack with enchants that do add stats. For example you can add rocket boots and +22 stam to boots (since crit has been removed from rocket boots), or hyper-speed accelerators and reticulated armor webbing (note: though both are engineering enhancements, armor webbing doesn't count as a true tinker because it adds a stat to your gear.)
Sorry for repeating what most of you already know, but it is important for clarification. The mind-amplification dish stacks with all other helm enchants, which is awesome because the dish still gives you the old +30 stam buff. While 30 stam isn't a ridiculous amount, it's the same as a free epic gem. Enjoy!