It is possible that this small country only has one exit node. Or only one exit node with an exit policy that allows what you're doing.
By choosing a country with only one exit, you restrict your possible exits to a set of only one, so every circuit you build will use this one exit.
If you go to the bottom of this page: https://torstatus.blutmagie.de/ you can:
- Sort Router Listing By: Country code
- Sort Order: Ascending
- Bad Exit, Hibernating: No
- Exit, Running, Valid: Yes
- Apply Options
That will show you all good exits by country.