In discussions with lsalzman we decided to use the full fix even for backports, instead of the less-risky-but-backwards-incompatible patch. Since that patch fixes tests we have, I landed the full fix there as an ostensibly non-sec defect fix.
Bug 1663466 Comment 37 Edit History
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In discussions with lsalzman we decided to use the full fix even for backports, instead of the less-risky-but-backwards-incompatible patch. Since that patch fixes tests we have, I landed the full fix there as an ostensibly non-sec defect fix. This is therefore fixed now in 85, and we need only backport to beta and esr(s?).