Uh oh! You've found an error in Core.
This happened while running your code, so you may be able to find a workaround, but is ultimately an issue in Core.
The following code caused the error:
yml_decode('test: 2022-07-01T18:30:00+02:00')
on or around Interpreter:1.
Please report this to the developers, and be sure to include the version numbers:
Server version: SHELL;
MethodScript version: 3.3.5;
Loaded extensions and versions:
Core (3.3.5)
CHFile (0.0.7)
Here's the stacktrace:
java.lang.ClassCastException: java.util.Date cannot be cast to a Construct type
        at com.laytonsmith.core.constructs.Construct.GetConstruct(Construct.java:382)
        at com.laytonsmith.core.constructs.Construct.GetConstruct(Construct.java:370)
        at com.laytonsmith.core.constructs.Construct.GetConstruct(Construct.java:337)
        at com.laytonsmith.core.functions.DataTransformations$yml_decode.exec(DataTransformations.java:256)
        at com.laytonsmith.core.Script.eval(Script.java:449)
        at com.laytonsmith.core.MethodScriptCompiler.execute(MethodScriptCompiler.java:3030)
        at com.laytonsmith.tools.Interpreter$4.run(Interpreter.java:832)
        at java.base/java.lang.Thread.run(Thread.java:833)