This has been discussed for subversion plugin and probably others too. But not seen an issue for the git plugin.
Add a path to the excluded regions section of the plugin. Make a change inside the excluded region. Kick off a build manually.
The change in the excluded region is listed for this build.
Not a build is not kicked off by this change - the polling honours the excluded region. It's just the changeset reported that's the problem. And hence the confusion.