The Death event on that image has a blue box round it. That means the edit has not been accepted. Try accepting it and see if that changes the display.
I have had a look at your site. The ASSO entries you added to the husband of this individual seem OK. But they are added to his Probate event, not death, so I do not understand why you think the two things are related.
When an event does not have a date, the system does attempt to calculate a likely date to use for sorting. It might be that in this case it is looking at the husbands date of death in error – but I cannot see anywhere in the code this could happen.