Sorry if this has already been posted but a quick glance and i didnt see it. For the gif I was scrolling through fast to see it occur but it has happened enough with organic usage I felt I needed to post. I checked two post from the video and its not reposted content. Upvoting one upvoted both, both have identical comments.
This is actually an issue with the Lemmy API that I noticed while working on my own Lemmy app. Basically pages are fetched from the api in order eg 1.2.3.4… and each of those pages can have up to 50 posts, I believe. Now say you fetch page 1, then browse for a bit before reaching page 2. Now during that time new posts were submitted, and now some of the page 1 content was pushed down to page 2. When page 2 is fetched it now contains a duplicate post from page 1 because the server doesn’t know the order or starting index from when you fetched page 1.
I think the api needs to add support for timestamps that it can be submitted with api requests so that fetching content is based on the time that page 1 was fetched.
As for this issue, if the developer is seeing this. I resolved this in my app by filtering out duplicate post ids when fetching new pages. It’s not ideal, but it’s all I could think of to do.
I'm not sure if this is the same issue, but often, as I'm scrolling through comments on a post, the comments will start over and repeat from the beginning. It'll continue as long as I keep scrolling, too. I never can make it to the end of the comments, as the list just keeps repeating over and over.