IL2CPP cannot find my managed dll

I’ve compiled a huge generated code class into a DLL, everything that used such class keeps working, except when I build with IL2CPP. It throws tons of 485479EBD42C96C53B48C971C9930EE0.obj : error LNK2001: unresolved external symbol QuickSystemFilter3EntityShared_5_OnCreateForCompiler_m3BE711B5A43269085FE5002C39D9EED26EC73180_gshared and the like.
QuickSystemFilter3EntityShared probably refers to:

public abstract class QuickSystemFilter3EntityShared<F1, F2, F3, S> : QuickSystemBase where S : struct, ISharedComponentData {
    protected override void OnCreate() {
        m_MainGroup = GetEntityQuery(typeof(F1), typeof(F2), typeof(F3), typeof(S));
    }
    protected override void OnUpdate() {
        Entities.With(m_MainGroup).ForEach((Entity e, S s) => {
            OnUpdate(e, s);
        });
    }
    protected abstract void OnUpdate(Entity e, S s);
}

which is one of the many classes on the DLL, which are used all over my code. Since it’s managed dll, I never bother doing any DllImport, could this be the issue?

This looks like a problem on the IL2CPP, side, not with your code. Can you submit a bug report and include this project?

sent as a bug report with the project