Thats becuase, this PR was NOT fixed as a S/w bug. So it does NOT mention of the fixed JUNOS release.
This PR required S/w enhancement to handle/support the scenario (its not bug). A enhancement request was raised but wasn't implemented. Quite old PR, there are a lot of changes in L2 code ongoing constantly, may be that this one has been addressed by some code change already. For more details, log a case with JTAC.