I tested the demo site you provided. I see that there is an XSS vulnerability. I hope you can check and provide a fix as soon as possible.
link video Poc
https://drive.google.com/file/d/1CEEFO0ukhjug6dNRfb-vdQNuBUyezoJp/view?usp=sharing
1 .Login as account demo
2 .Access the module issues
3 .Then create an issue
4 .Pass the payload into the Tittle field
Payload
test"><script>alert(document.cookie)</script>
5 .After creating issues , click on the newly created issues, the payload will be executed