You cant set ezcountry field in content type to multiple choice and set more than one default value with one transaction. You must first set multiple choice, save draft, and then you can set multiple default option.

Prerequisites - none

Steps:

1. Go to Admin > Content type
2. Click Content group
3. Create new content type
4. Add Country field
5. Check multiple choice
6. Select two country as default
7. Click Publish

Actual result:

You can't publish - error tells You that field definition don't allow such action.

Expected result:

Content type published with ezcountry field with two default values.