A scripted object has a different serialization layout when loading errors in web build

[P_Y_000]

Hello, everyone, here’s a little story about how anincomprehensible error can ruin participation in the Crazy Web Game Jam event. To speed up development, I used the Game Creator 2 package from Catsoft Work, which I love.

It occurs during runtime gameplay. When the scene has loaded, game freezes and the console shows this error.
I tried several options but nothing helped.

Unit version: 6000.0.23.f1

A scripted object (probably GameCreator.Runtime.Characters.Character?) has a different serialization layout when loading. (Read 776 bytes but expected 1448 bytes)
Did you #if UNITY_EDITOR a section of your serialized properties in any of your scripts?

[P_Y_000]

I found the cause of this problem.

My file with a custom class used in Character.cs got into one of the subfolders of the Editor folder.
I did not notice this.

This led to the fact that the class did not exist in the build.