RandomSpawn not working at all with CatServer

Summary

With CatServer, RandomSpawns with ADD feature are causing error SPAMMING in the console (see pastebin) and are broken.

Steps to reproduce

• Install a fresh CatServer (https://github.com/Luohuayu/CatServer/releases) by downloading the CatServer-1.16.5-1d8d6313-server.jar and your start.bat
• Execute the start.bat
• Get the last version of MythicMob available (was 5.6.2).
• Restart the server to let the plugin create its files (you may encounter an error like java.lang.NullPointerException: Cannot invoke "io.lumine.mythic.core.mobs.MobExecutor.isActiveMob(java.util.UUID)" because the return value of "io.lumine.mythic.bukkit.MythicBukkit.getMobManager()" is null), if so, restart the server one more time
• Go to plugins/MythicMobs/config/config-spawning.yml and set GenerateSpawnPoints to true
• Add a simple randomSpawn example like so [https://pastebin.com/adLNu2eA]
• Last step will be to join your world to trigger the spawning

Server log file

[https://pastebin.com/M8Y1Vet9]

Additional informations

Using MythicMob 5.1.0, everything is fine, no console error and mobs are spawned perfectly. Then, the RandomSpawn system got reworked and does not work anymore with CatServer.