No predecessors and calculation is on.
While anonymizing the plan I played around a bit more and found that when I change scheduling to "From project start date" instead of "From project end date" the issue disappears.
Nevertheless, I would like to understand this as it didn't happen with the mpps I created before and they were scheduled the same. Maybe it's an accumulated issue as the plan is based on a template?
Appreciate if you could have a look