Project couldn't be exported: U_STRING_NOT_TERMINATED_WARNING

Summary

Project-Export couldn't be exported. This only occurs on one of my repos: https://gitlab.com/engineering-projekt/examibur/

Steps to reproduce

1. On https://gitlab.com/engineering-projekt/examibur/edit, click on Export Project

What is the current bug behavior?

An Email with the Error U_STRING_NOT_TERMINATED_WARNING is sent.

What is the expected correct behavior?

The download Link should be present in the E-Mail.

Relevant logs and/or screenshots

Full E-Mail contents:

Project examibur couldn't be exported.
The errors we encountered were:
U_STRING_NOT_TERMINATED_WARNING

Output of checks

This bug happens on GitLab.com