1. switch on editing mode
2. hide a file/assignment
3. move the hidden file/assignment from one section of the course to another section
here error #1 occurs: the moved object is visible now
4. switch off editing mode -> file/assignment remains at the location, where it was drawn
5. switch editing mode on again
6. hide file/assignment again
7. move file/assignment again (within the same section)
error #1 again: the moved object is visible now
8. hide file/assignment again
9. turn off editing mode again-> here error #2 occurs: the just moved object jumps back to the position that it has after the first move

That error #2 occurs you first have to move a file/assignment from one section to another and then move within this section.

I tried to reproduce these 2 errors on "demo.moodle.net", but here works.