react_file_uploader | React and Express file uploader | File Upload library

I have a problem that I can't find a solution for a long time. It only happens when uploading a file that is already in the upload folder (file with same name). If I upload file for the first time it works fine. I'm using express-fileupload package.

I used this code as a reference https://github.com/bradtraversy/react_file_uploader

My form worked fine until I added file upload, first I thought that its something wrong on the front end, I use React and thought there is some state that is changing and causing the page to reload, but later I used Postman and it still reloads my app, doesn't matter on what page I am, even If I log out and upload the file with the Postman it reloads the page, but only if the file is already uploaded. This doesn't happen in the code above.

This is how my code looks

controller/upload.js