Automated Email still send notification

Hello, First of all thank you for helping me in comment section under "themeforest " under cristechservice name. The code from https://wplms.io/support/knowledge-base/lock-assignment-after-submission/ looks good and really to avoid student to submit another or update upload assignment however I have the following issue that is not solve again

1. When student submitted the assignment it redirected to new tab says " Assignment Under Evaluation " based on the code above. however when student visited the assignment again even though it says " Assignment Under Evaluation " both instructor and student receive new notification again stating that

for student: you submitted assignment xxxxxx for instructor : student submitted assingment xxx how to prevent this from happening , we dont want any notification everytime student visit the assignment , instructor take 10-15 days before they release the marks,

1. Another issue when instructor upload file assignment to attached on the student we got the error says " There is a space in file name, Please remove space from your filename and try to re-upload again" can allow even thou they spaces?

2. is there a way co-instructor can have access on a specific unit for example : mark the assignment and download the assignment without having the ability to add students on the course.

Thanks and looking forward