The following example is incorrectly parsed:
X properties allow multiple values, but the quotes are ignored. The result is two properties: "geo:10.123456 and -70.123456". The attached patch fixes this.
However I'm not sure if the correct output should be "geo:10.123456,-70.123456" or without the quotes. If you remove the VALUE=URI parameter then the result becomes escaped as \"geo:10.123456\,-70.123456\". These are separate issues based on how icalvalue handles different property types and I'm not sure if they're behaving as intended or not.