Have just noticed a behaviour which I think is very counter-intuitive. I can see why Atlassian might think it is making things easier, but it isn't.
Basically, if you are looking at a next gen board/backlog etc. through filters (the quick filters they give you at the top, such as person, label, type) and you click a 'create issue' within one of the columns, then the system will try and populate the fields of the issue from whatever filters you have selected.
e.g. I had filters on for 5 people. I went to create a new task for myself. Typed a line and pressed enter - and Hey Presto, it created the issue, assigned it to someone and sent them a notification. I wanted the issue to be mine, so I changed the assignee but the notification had already been sent. Even 'better' the assignee it chooses is based on the most recently added filter, so if I click on 5 people quickfilters, , I have to remember which order I clicked on them to predict who new stories will be created for. Undoing this is a pain. Would be much better to have the default as the currently logged on user and you have to change the assignee later.
I can see where this is going, because the 'reuse fields from last thing I created' is useful, but on these boards it is hard to predict and scares the timid users