I can not see changes in any merge request

Hi!
I have GitLab Enterprise Edition 13.12.11

In one project, when I try to see changes in any merge request I see

gitlab1093×304 6.52 KB

In inspect I see

Uncaught TypeError: Cannot read properties of undefined (reading 'push')
    at utils.js:581
    at Array.forEach (<anonymous>)
    at utils.js:548
    at Array.reduce (<anonymous>)
    at utils.js:544
    at tree_worker.js:12

Would be really happy about any hint how to solve it!