@vladikoff, found and fixed the problem.
In building out a talk on Grunt talk, I found some tasks would silently not run. Eventually I found that by commenting out the grunt-html-validation plugin these tasks would start working normally again. See Issue #1, in that talk's project.
This project is for recreating and investigating the failure conditions.
In this project I try to combine html validation with imagemin, which depending on the order they are run will cause strange behavior. If validation comes before imagemin, imagemin will still run, but not operate on any files.
Issue is not present with html validation v0.1.13, but exists v0.1.14+
] grunt imagemin-fails
# imagemin will not operate on src/img/test.png
Running "clean:0" (clean) task
Cleaning dist/index.html...OK
Running "clean:1" (clean) task
Cleaning dist/test.png...OK
Running "validation:src" (validation) task
Validation started for.. src/html/index.html
>> Validation successful..
Running "imagemin:pngs" (imagemin) task
# why is nothing happening here?
Running "copy:html" (copy) task
Copied 1 files
Done, without errors.
grunt imagemin-works
# imagemin will operate on src/img/test.png
Running "clean:0" (clean) task
Cleaning dist/index.html...OK
Running "clean:1" (clean) task
Running "imagemin:pngs" (imagemin) task
src/img/test.png (saved 9.33 kB - 15%)
Minified 1 image (saved 9.33 kB)
Running "validation:src" (validation) task
Validation started for.. src/html/index.html
>> Validation successful..
Running "copy:html" (copy) task
Copied 1 files
Done, without errors.on node v0.10.26 / Amazon Linux
on node v0.10.26 / OSX
@vladikoff via Freenode #grunt.js for help