It was detected when I was testing the modpack in version 0.0.4 alpha.

• Sometimes when the mod's HUD is rendered when join world:

Stack-trace warn: "Unexpected error";
Light error-line: "at com.craftingdead.core.client.ClientDist.handleRenderGameOverlayPre(ClientDist.java:587) ~[?:0.0.4-alpha] {re:mixin,re:classloading}";
Full error stack-trace: https://pastebin.com/CqEtfWE1;
Full client log: https://pastebin.com/JbQqfN40;

I was using forge-31.2.45 to run it and Optifine for better rendering performance.
(This happened even without using Optifine)

This is a known issue, it's going to be fixed as part of a rewrite of some of the mod's internals.