JEM has 3 possibilities to handle past events: do nothing, archive (after x days), delete.
For me it's normal, to archive after 1 day. So all past events are in the archive and in simplelist the next event is always on top (only exeption: events with no dates are first on top)
It seems to get some problems on simplelist, when the general JEM setting is: do nothing ( = not archive).
EDIT: I think, the problem of Jaenino has to do with this.
I tested this commit (even I prefere using the archive setting).
Now you can have in simple list either Load more or pagination.
This was really hard to understand and reproduce this issue!