Discrepancy in comment and upvote count on different instances

I noticed that when I view this post for example on lemmy.world: https://lemmy.world/post/291005 and on dataterm.digital: https://dataterm.digital/post/54221 that both of them are the same post but with a different number of votes and comments.

I believe this also leads to different sorting of the all feed in these instances. Why is that and can it be fixed? Is it even a bug?

I even saw while having both posts open that on lemmy.world a new comment got added in realtime but not on dataterm.digital