PreEmptive Dotfuscator: Obfuscation fails for Xamarin.Android project with "Reference to undefined class 'UNKNOWN_OWNER'"

I followed the instruction on how to install and add PreEmptive Dotfuscator Community Edition on a Xamarin project (in my case Xamarin.Android). Building with Dotfuscator enabled, failed already on the first try, but the config file was generated thou.

I managed to figure out that I had to add a few custom assembly load paths. Because Xamarin installed all the Xamarin.Android packages in C:\Microsoft\Xamarin\NuGet.

After I got rid of that error, the next occurred with the following output:

Class 335:  UNKNOWN_OWNER
Error: Reference to undefined class 'UNKNOWN_OWNER'
Could not create output file, error code=0x80004005

***** FAILURE ***** 
ilasm returned 1

System.ApplicationException: ilasm returned 1
   at lk.a(ISession A_0, f7 A_1, List`1 A_2, String A_3, String A_4, Boolean A_5)
   at lj.a(ISession A_0, f7 A_1, List`1 A_2, String A_3, String A_4, Boolean A_5)
   at lu.a(ISession A_0, f7 A_1, d1 A_2, String A_3)
   at lu.u(ISession A_0)
   at lq.a(Dictionary`2 A_0)
   at lq.a(IOptions A_0, qz A_1, Dictionary`2 A_2, h9 A_3)
   at lq.<>c__DisplayClass22_1.<Run>b__0()
   at lq.b(Action A_0)
   at lq.c()
Build Error.

I tried to disable and enable different options like the 'Library Mode' and I checked if the error would go away by excluding parts of the project a few at a time. The project does build and run when Dotfucator is disabled.

I tried my luck with Google for an answer like usually but with bad results this time. So my last hope are you guys. Please, does anyone know what this error means and how to fix it? Is there a way to know which class is 335?