An error was reported when submitting formdata

When I submitted files via formdata using fetch-event-source, small files were successfully submitted normally, but files over 50k directly reported an error. The error is as follows:

<img width="752" height="624" alt="Image" src="https://github.com/user-attachments/assets/98977d9b-08d1-4b9e-992b-fba46bed4cd7" />