I spoke with a FA about this exact thing today on one of my flights. He said that these passes only allowed them in J after all pax have been upgraded. These are gate standby upgrades that do not require them to rely on the gate agent to "hopefully" upgrade them.
I can't say that I have a problem with this either. These are special passes, not a perk they receive on every pass they use.
Enjoy them AC staff, I haven't forgotten what
we all went through together in August. You all did a great job regardless of the family affiliations