I've identified the issue. The game uses different stats for health when Survival Buffs are enabled from the new Apex Survival update. The stats are defined by MyObjectBuilder_MaxHealthBuffDefinition in EntityComponents.sbc

I've made a patch for this mod that works with Survival Buffs enabled here: https://gtm.steamproxy.vip/sharedfiles/filedetails/?id=3575343225

Feel free to incorporate this change into your mod if you like.

I think this is broken with the latest update