Problems opening new attempts at group-grading assignments

Ok, here is now a much smaller test case, which seems to cover both of the issues I first posted, so I replace the first, messy post by this. Hopefully this helps to resolve the issue quickly-ish.

It seems like the student first added to a group gets a different treatment than the others in the group. I did the following steps:

1. In a test course with two test students put in the same group, I create a new assignment. Attempts are set to reopened manually and group submission is set on. The rest of the settings are left at their defaults.

2. A student hands in a pdf.

3. The teacher clicks the grading icon corresponding to either student in the grading view inside the assignment. He annotates the pdf, gives some points, allows a new attempt, and saves. The result is that the grade of student first added to the group goes back to -, and this student can see the annotated pdf in the assignment function. The other students in the group keep their grade, but they cannot download the annotated pdf. The next attempt has number 3, because opening the new attempt surprisingly seems to use one attempt. It does not seem to matter which student hands in the pdf or which student is graded.

4. Alternative to 3: The teacher annotates the pdf, gives points, and saves, but does not allow a new attempt. Both students can download the annotated pdf next to the pdf logo. Neither student's grade gets reset to -. Now if the teacher allows a new attempt manually in the grading view, then both students still keep their grades, they can download the annotated pdf, and the next attempt has number 2. All of this is expected behaviour.

Another alternative: Do everything as in steps 1-2, but set attempts to be reopened automatically until pass. Go to the gradebook to set minimum grade for pass for this assignment to 1. Student now hands in pdf, teacher grades with zero. No new attempt is automatically opened, which seems incorrect to me.