Why are the color categories of letters on the general mailbox affixed with a delay?

Question

Outlook

Good afternoon. After migrating from 2007 to 2016 office, users working with shared mailboxes began to notice that changes were reflected with a delay when setting color categories. The situation is as follows: there are five people, each of whom marks the letters that came to the common mailbox with their own color and then works with this letter. The rest, seeing that the letter has been accepted for work (marked in color), do not touch it. In 2007, everything was fine, the categories were put down, people worked quickly. In 2016, after putting down the color, it takes several minutes until everyone sees it. In this case, the whole point of such marks is lost: several specialists are working on the same letter. They work with different versions of windows 7 (x64, x86), the office version is the same - MS Office 2016 Standard x86 Russian. I won’t say anything about the servers right off the bat (I’m enikey), but I can make inquiries. I will also add that KES10 is installed at all stations, and with the same configuration of other software and hardware, there were no such things since 2007 office. We have already tried to recreate mail profiles with deleting files, reinstall the office itself from scratch and even reinstall the system -
Does not help. Is it possible to tweak or add something, or put up with and nod in the direction of admins and servers with their speed? Maybe someone knows the official explanation from MS?