Macros targets met but calories are way under. Macros not adding up to calories.

I have searched and found this same question but the answer doesn't really make sense. The last time it was asked was a long time ago so I thought I would post it again. When I've hit my proteins, fats and carbs for the day the diary is showing I still have over 100 calories left. I understand that food labels can round up. I don't understand being this far UNDER my calorie goal when I've met my macros for the day. Any ideas?