If set to DE SCA attempts to complete every telephone number that is NOT in international format with a German area code. This default set to DE is only usefull for German customers.
So in SCA v2.0.19 we changed it to false which is the recommended value of this setting now.
More on this topic please see here.
Are you affected?
You are NOT affected by this change if you are an international customer OR if you have already explicitly set PhoneNumberParseCountryCode_Option.