The gap shown between the back of the bucket and the ssqa plate is a problem that needs to be diagnosed and understood.
If this side has a gap, and the other side is tight, that suggests xfaxman is correct and the connecting tube is twisted.
If both sides show the same gap, that suggests the upper angled part of the ssqa is not fitting correctly into the angled part of the bucket. One or the other could be bent.
Or, you need to juggle the bucket on the ssqa before inserting the pins to make sure the back of the bucket and the ssqa plate are tight on both sides.
Maybe borrow a bucket or other ssqa attachment from a neighbor and see if the problem stays the same or goes away.