I just bottled an extract pale ale (with half a pound of crystal malt) and it has a very strong DMS taste. I'm quite confident that this is what the flavor is, as it's something I often taste in pale lagers, but never elsewhere, and has a cooked vegetable type flavor. The flavor is much stronger in the smell than the taste, but is present in both. The only thing I can think of that I did differently is that I added half the extract later than I usually do (though I have been doing late additions all along) and didn't reach a full boil after adding the late addition.
Has anyone else experienced this problem? Are there any other possible causes?