Hi @VladimirAlexiev, thanks for taking the time to report this! Unfortunately this Wikimedia Phabricator task lacks some information.
If you have time and can still reproduce the situation: Please add a more complete description to this task. That should be

• a clear and complete list of exact steps to reproduce the situation, step by step, so that nobody needs to guess or interpret how you performed each step,
• what happens after performing these steps to reproduce,
• what you expected to happen instead,
• a full link to a web address where the issue can be seen.