These changes are implemented in a backwards compatible way. For
applications compiled on Mac OS X v10.4, these filters continue
to behave on Mac OS X v10.5 as they did previously.
I can compile a test application on Mac OS X 10.4.10 and the
gradient will indeed render backwards in 10.5. :-/
Please file a bug report for this, then; I'm pretty sure the
documentation is [supposed to be] correct in this matter.