Obviously the event was tested green and the bug appeared/was found out after. That's why it was announced in the maintenance information yesterday. Not 1 week ago btw.
ok man but systematically its like 8 months that we get bugged contents on the events , so the things are 2 : your staff is not making any test. Your programmers are unable to apply the changes into the playing servers. Maybe make a test server and use it to see if something is bugged or not, its impossible to go on like this