Test case: http://persistent.info/webkit/test-cases/animation-alternate.html
Expected result: gray box moves to the right and then back to the left.
Actual result: gray box moves to the right, jumps back to the starting point, and then moves again to the right.
This happens with both WebKit Window nightly builds and the Chromium canary channel. I haven't had a chance to narrow down the regression range, but it works as expected in the Safari 5.0.2 release but is broken as of r67637. Chromium noticed this breakage with r67098 (see bug 45512), though I don't see how that would affect Windows only.
This works in my TOT mac build.
Added related test failures to the Skipped file in r67866. http://trac.webkit.org/changeset/67866
Created attachment 68123 [details]
*** Bug 45512 has been marked as a duplicate of this bug. ***