Engagement and disengagement are effectively separate forms of labor expected of an employee, though, and they're virtually never formally codified. If I'm a coder and my job is to write code, don't expect me to be enthused about writing terrible medical billing software. Enthusiasm and engagement are emotional labor, which I'm not compensated for, and which, to some extent, you can't realistically expect me to demonstrate. I'm not able to "be engaged" beyond performing my tasks and whatever technical or administrative duties I've been assigned. Expecting me to contribute in a way orthogonal to that requires my job to be fundamentally different from what it actually is.