probably the problem is that you have 5000+ sources, and you output selectors in the process interface - because of which the browser takes a long time to render such a selector
You need to delete extra channels. Since their creation is not a system error, you have several ways to solve the problem:
1. we can remove sources according to the conditions you specify for 1 hour of revision
2. we can do it for free if you move to the cloud
3. if you have personal technical support - you can contact it
4. delete sources manually
I don’t see any reasons for resuming the ticket
https://crm-onebox.com/ru/support/business-processes/8609-zapisat-istochnik-kana... - you were given an exhaustive answer about that the functionality used worked correctly. Whether it was true that you decided to use it is another matter altogether.