I had smooth scrolling turned on for day view and week view.
Never experienced this happen before I turned that on.
Have now turned it off, and appears ok again.
When dragging a task in week view, if smooth scrolling is turned on week view will jump to the next or previous week after the task is dragged.
The task goes to where I want it, which I find out after swiping back to the week.
It happens so fast, I don even get to see the task moved to the new day before the screen jumps.
Not sure it happens every time, maybe more to do with where I am grabbing the task and where I am dragging to and releasing my finger.