Hi all!
I haven't slept for five days 
There is a board (Scrum) with columns (To Do, Testing, Done....) on which some tasks are not displayed.
If you look at the board filter, all the tasks are there. And if you look at the columns - the number of tasks is equal to the filter. But, on the board itself, the number of tasks is different, less.
All other filters (dates, owners, etc.) checked - everything is ok.
What else to check?