Custom ContextAssociationManager CDI problem

for couple of hours I have been trying to force Camunda to use my custom ContextAssociationManager. But I am unable to solve the CDI. I added MyContextAssociationManager to META-INF/services and it seems it gets loaded properly.

The problem is that when I try with no annotations in MyContextAssociationManager I get

Ambiguous dependencies for type ContextAssociationManager with qualifiers @Default

of MyContextAssociationManager and camundas DefaultContextAssociationManager (which MyContextAssociationManager extends). I expected that @Specializes annotation shoud have fixed that but when I add this to MyContextAssociationManager I get

Unsatisfied dependencies for type ContextAssociationManager with qualifiers @Default

And this is what puzzles me. I either have 2 possible dependencies or none. Could you please give me a hint of what might be going on?

Other than that I would be very thankful if you could explain the mechanism how the ContextAssociationManagergets is being produced because I could not find any producer methods or annotations or any usages of ContextAssociationManager in code other than the inject from BusinessProcess.