I needed to call a connector many times in a row, i created a call activity with iteration (sequential multi-instantiation). After a while it stops working with ConcurrentModificationException, after starting it over again it doesnt stop with the same data, it stops randomly. I started over again and again, always deleting the elements that was already finished, after 7 restarts it finished.
To me it looked like a random error, what causes this error? How to get around this?