This feature keeps confusing our lecturers/teachers because it seems to imply that a student can choose to edit the first attempt for an assignment after the first attempt has been graded.

I could rephrase the wording myself, but since we never need this option I would opt for an option to enable or disable this feature in the assignment settings under 'attempts'.

The removal of this button has been discussed and requested earlier in the forums:

https://moodle.org/mod/forum/discuss.php?d=343957

https://moodle.org/mod/forum/discuss.php?d=436181

Also other people seem to find it confusing:

https://moodle.org/mod/forum/discuss.php?d=464071