I agree that it's a bug and should be fixed. I just don't agree with the implication of the title that it's a super huge deal. I mean, all we're doing is swapping out mov for push and leave. The functionality is completely unaffected, and the slowdown is so minor that no one would ever notice without running a ridiculous microbenchmark.
Fix the bug, but don't make a mountain out of a mole hill.
Fix the bug, but don't make a mountain out of a mole hill.