Lemmy Devs - Why do the upvote and downvote numbers for a post change in front of my eyes when viewing a post?

Buggy looking behaviour observed, when I view a post on another instance or make a post on another instance then go back to viewing it, in front of my eyes, I can see massive disparities in the amount of upvotes and downvotes. Talking a post showing 600 upvotes then a few seconds later, 5 upvotes, then 40 etc