Until now, whenever you pushed a modified gemspec to a repository that is gem enabled, we rebuilt it, no questions asked. This was convenient if you needed to fix a broken gem version, but had the very undesirable side effect of making it very easy to accidentally overwrite a good gem release with a broken development version.
We recently changed the system so that only gemspec pushes that contain a bumped version will be built. This will prevent accidental gem clobbering and we can now guarantee that when you release a specific gem version, that version will never change. The downside is that if you botch a release, you’ll need to bump the version in order to get a fix out. This is a small price to pay to ensure that good gems don’t get overwritten by bad gems.