Shield modules got their additional rebalancing during the same patch that nerfed resists overall (18.04 - shield hardener tiericide):
This Tiericide pass coincides with the global 20% reduction in resistance values for all resistance modules, therefore for some modules that change might be different than 20% from the attributes on Tranquility before the patch.
Armor only had the overall resist nerf applied until now.
I’m assuming you’re referring to this? In case you got confused, this is a BUFF for layered coatings and adaptive nano membranes (now called multispectrum coating).
The A-type adaptive used to be ever so slightly worse than the C-type energized adaptive, but right now it’s actually better since the energized versions haven’t been rebalanced yet.
Invest in blingy energized adaptives now while they’re cheap! CCP will probably finish rebalancing on them next patch