Skill Invocation API: Session Attributes in response are encrypted and not readable

My custom skill sets session attributes inside the LaunchIntent.

I'm implementing automated tests and therefore using the Skill invocation API (https://developer.amazon.com/docs/smapi/skill-invocation-api.html ). I'm using the invocation API over the simulation API because I want to test sending game engine requests to the skill.

When I get the response back from the invocation api the session attributes I did set in the skill are not present.

But the invocationResponse JSON contains only some strange sessionAttributes entry:

 "invocationResponse":{              
	"body":{                 
		"version":"1.0",               
		"sessionAttributes":{                    
			"SIS-ENCRYPTED":"AAAAZIQd___very_long_string____"            },

I want to verify the correct sessionAttributes are contained in the response. How can I read them?

Thanks for your help!

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