Thanks so much! Changing the config value -keep @interface * to -keep @interface * {*;} seems to have fixed it! It would be great if the documention had a section which talked more about annotations and how to configure ProGuard to deal with them as you want it to. I should note that I still think this is a bug since I'm obviously using the given annotation parameters in my code, so ProGuard should know better than to remove them since I'm telling it to keep the class and the annotation.
This bug also occurs with the javax.inject.Named annotation, but not with the org.springframework.beans.factory.annotation.Value annotation.
I was also able to reproduce this issue on v6.0.2
ProGuard shrink removes parameters from some annotations (even w hen it keeps the annotation itself)