It's happened to me before. I don't know why you sometimes get comment and upvote data, and sometimes you don't (it's not because of me being the first subscriber on my instance). When it's happened, I didn't get the old data, but I did start receiving stuff from the date I joined, so if you can see this comment on your instance's copy, then that's something at least.

Looks like you've already received an answer but if you check this community's sidebar, you'll find the following statement:

This community is for issues related to the Lemmy World instance only.

In case you run into additional issues that aren't specifically related to this instance later on, these communities may be useful:

!lemmy@lemmy.ml - "Everything about Lemmy; bugs, gripes, praises, and advocacy..."

!lemmy_support@lemmy.ml - "Support / questions about Lemmy."