Add an assignment to a course with these global and particular settings:

1. In Site administration > Advanced features:
Enable completion tracking and conditional access.

2. Course: Enable completion tracking.

3.a. Add an assignment and set:
Activity completion.
Completion tracking:
Require grade: Student must receive a grade to complete this activity.

So, completion tracking must work like this:
When the assignment is sent but not graded, the check box must remain empty until the assignment has a grade. Then, when is finally graded, it shows a blue tick no matter what grade it was.

3.b. Add an extra condition to the assignment and set a 'Grade to pass'.

So, completion tracking must work like this now:
When the assignment is sent but not graded, the check box must remain empty until the assignment has a grade. Then, when is finally graded, it must show a green tick if it pass or a red cross if it fail, but actually it works this other way:
When the assignment is sent, immediately it shows a red cross instead of remaining empty until it was graded.

I actually left a previous message in assignment forum (https://moodle.org/mod/forum/discuss.php?d=235244#p1021700) but I guess this is the right place instead.
Thanks!