Has anyone ever encountered a situation in which the Minimee tag pair (using version 2.1.10) correctly outputs a minified CSS file to the cache directory, but the JS tag pair simply has no effect at all and the various JS files wrapped with the Minimee JS tags simply wind up as-is in the template? In both cases the files are static CSS and JS files loading from the local server. But the CSS files are being combined, while it seems like the minimee js tag pair is being ignored.
Most often the cause for this is that one of the JS files you're trying to use does not exist (at least from Minimee's point of view). As Alex suggested, if you turn on EE's template debugging, Minimee will add errors to the log. Search for the string "Minimee [ERROR]" to jump right to where it's encountering a problem.
If you install the EE Debug Toolbar, Minimee adds its own panel of log messages, so it is even simpler to track down what might be amiss.
Feel free to hit me up direct via twitter (@johndwells) if you're still having trouble, or the devot-ee forums if it looks like there's a bug.
I haven't ever seen that myself. Is the
exp:minimee:js tag closed properly?
The first thing to do is turn on EE's template debugging feature because Minimee will provide debugging info there with any errors. http://johndwells.github.io/Minimee/#faq