Hi there! I'm not sure if this is more of an issue with SpartanShields, but when I equip a shield from that mod I don't get the 5 hearts bonus from the Defender class.
Would it be possible to add a config option to specify item ids that could count as a valid shield? or is this just a problem with Spartan Shields that they need to flag or add a "check" or something to make their shields read as Minecraft vanilla shields?
I saw this issue already fixed, not sure if related or not:
09330b5

And here is Spartan Shields if more info needed on that mod:
https://minecraft.curseforge.com/projects/spartan-shields

This was confirmed to be an issue on SpartanShields' side:
https://minecraft.curseforge.com/projects/spartan-shields/issues/20