Your comments

Yes, it's the same issue! I also tried to work around it by reducing call stack depths with inlining some fsSerializer methods but it hasn't worked out so we're having to wait for a engine fix.

The current solution is to not use any embedded graphs at all (even a very simple flat one embedded into a scene will not work).

Thanks for the heads up, we're expecting to switch to Bolt 2 as soon as it is stable. Already figured it probably isn't changeable easily so I'll see if unity can provide a solution, because other IL2CPP platforms don't suffer from this issue.

Did you create AoT stubs (Tools/Ludiq/AOT Pre-Build)?

The repro project runs on Mono, which makes this really puzzling for me.

Probably for the DLL distribution not viable, but "#if ENABLE_IL2CPP" could be used? (Source: https://docs.unity3d.com/Manual/PlatformDependentCompilation.html)

I replaced 1.4.3 with 1.4.0f11 and it works again, so that's probably a regression?

Edit: 1.4.2 also still worked, so that's good news for me because I can easily downgrade ;-)

Apparently a upgrade of the project with 2018.3 and Bolt 1.4.0 to 2019.1 had no problems, but now using 2019.1 and upgrading to 1.4.2 it breaks as Bolt will never upgrade itself due to the exception (see callstack in my first post). I tried faking the version values in all the ProjectSettings for each Bolt component but apparently that hack was either wrong or didn't work out ;-)

I'm really suffering from this issue. Bolt worked well, but I upgraded to 1.4.2 and now nothing works anymore, all graph inspectors just tell me to "Open the Upgrade wizard" but it refuses to do so. Updating Unit Options still work, but that's all. Any estimate when the 1.4.3 is available? The does-not-find-units-in-asmdef bug fixed in 1.4.2 is a real showstopper for me.

Callstack when the update wizard won't open:

TargetParameterCountException: Number of parameters specified does not match the expected number.
System.Reflection.MonoMethod.ConvertValues (System.Reflection.Binder binder, System.Object[] args, System.Reflection.ParameterInfo[] pinfo, System.Globalization.CultureInfo culture, System.Reflection.BindingFlags invokeAttr) (at <1f0c1ef1ad524c38bbc5536809c46b48>:0)
System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) (at <1f0c1ef1ad524c38bbc5536809c46b48>:0)
System.Reflection.MethodBase.Invoke (System.Object obj, System.Object[] parameters) (at <1f0c1ef1ad524c38bbc5536809c46b48>:0)
Ludiq.AnnotationUtility+Annotation.set_gizmoEnabled (System.Boolean value) (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Utilities/AnnotationUtility.cs:190)
Rethrow as UnityEditorInternalException: An error occured while accessing internal Unity Editor functions. This might happen if Unity makes backward-incompatible changes in their newer versions of the editor.
Ludiq.AnnotationUtility+Annotation.set_gizmoEnabled (System.Boolean value) (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Utilities/AnnotationUtility.cs:194)
Ludiq.AnnotationDisabler.DisableGizmos () (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Interface/Annotations/AnnotationDisabler.cs:20)
Ludiq.UpdateWizard.OnShow () (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Windows/UpdateWizard/UpdateWizard.cs:70)
Ludiq.EditorWindowWrapper.CreateWindow () (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Windows/EditorWindowWrapper.cs:24)
Ludiq.EditorWindowWrapper.ShowUtility () (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Windows/EditorWindowWrapper.cs:83)
Ludiq.Wizard.Show () (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Windows/Wizard.cs:47)
Ludiq.PluginContainer+<>c.<initialize>b__16_12 () (at C:/Users/lazlo/Projects/Bolt1/Package/Ludiq.Core/Editor/Plugins/PluginContainer.cs:296)
UnityEditor.EditorApplication.Internal_CallDelayFunctions () (at C:/buildslave/unity/build/Editor/Mono/EditorApplication.cs:209)