variables' save attribute is not working

Summary

Variables are not persisting across server restarts despite the save attribute

Steps to reproduce

One can simply spawn this mob and then restart the server: when the mob first spawn, it will spam the value of the variable in chat. When the server reload, it will do the same, but this time the variable will be UNDEFINED

VariableProblem:
  Type: WITHER_SKELETON
  Options:
    Despawn: persistent
  AIGoalSelectors:
  - clear
  AITargetSelectors:
  - clear
  Skills:
  - setvariable{var=caster.test;val=1;save=true} @self ~onSpawn
  - command{c="say <caster.var.test>"} @self ~onTimer:20

Current behavior

The save attribute does nothing

Intended correct behavior

The save attribute allows the variable to be saved across restarts

Versions

• Minecraft: 1.19.4
• Paper: 527
• MythicMobs: Dev Build 4516