Upvote and Comment amount is inconsistent between my instance and other public ones

I just set up my instance and noticed that posts on my Instance dont have the same upvote and comment counts? What couses this and how can I solve it?
Example: https://lemmy.ohaa.xyz/post/151 - 26 Upvotes and 12 Comments
https://lemmy.ml/post/3331957 - 611 Upvotes and 54 Comments