Yep, there seems to be a bug in #Lemmy. I made my post from #Kbin, a similar software like Lemmy (and honestly, actually better).
Lemmy, or some instances of Lemmy, can not see or interact well with Kbin accounts and instances. For some it works, for many it doesn't. It can also be because the instances are getting too much requests than they can currently handle… so there are requests that are delayed or just stops working.
Anyway, yep, most users expect to see the older posts. If I am not mistaken, there are some fediverse software trying to find a way to add backfilling without hitting the performance (especially if the account have hundreds to thousands of content already).