Alright so here's what I usually see:
- Should the Besieged Modifier be positive?
- Is there a hidden malus that's causing the population loss? Whether I add the displayed modifiers or multiply them, I don't see how I'd be losing population.
- If it is intentional, should I really be losing so much population when I'm not blockaded?
EDIT: My governor is also adding a bit of negative growth, so that could be it. It's only -1 so I don't know if it explains everything. Besieged being positive is still odd.