I’m wondering if they cleared non-revs into C+ and moved the PM from C+ to PS to clear a space for a non-rev.

While it’s easy to feel like you’ve “wasted” the upgrade, what I’ve learned using certificates is that the biggest benefit is in not having to worry about whether it will clear. Since upgrades to international PS and D1 are not a medallion benefit, and such upgrades are a bonus and not to be expected.