Fatal error: Class 'Illuminate\Foundation\Application' not found (deploying on amazon eb)

I deploy on amazon elastic beanstalk and get this error

Fatal error: Class 'Illuminate\Foundation\Application' not found in /var/app/current/bootstrap/app.php on line 14

Does anyone know why this is happening?

Level 9

Have you run composer install?

Level 5

when you deploy on amazon it runs composer automatically

I found a fix online, but i dont understand why this is happening

if I run composer update --no-scripts everything is ok

does anyone have any clue why this is happening?

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