What is the problem with resetting the printer settings?

Question

macOS

The problem is this: there is an MT (RB2011uias-2hnd-in), a Macintosh computer (OS Sierra), 2 brothers network printers (L2720DWR).
Both printers are connected via WIFI to the MT. One stands in one office, printer2 in the office with a poppy.
We set up printer number 2 on the mac, everything works. (although it scans slowly, in "excerpts") (new firewood everywhere, all last update firmware).
After some time (a day or two, or after restarting the Mac), the following happens: when scanning documents on printer2, scanning occurs on printer1. (with the correct printer selected in the scan menu). When I try to print, it prints on printer2.
In general, as if the setting for accessing the scanner is lost.
It would be possible to solve the problem by connecting via cable, but it is necessary via wifi.
(What else could be the problem that it takes a long time to scan? I scanned part of the sheet and it costs 5 seconds, then again part of the sheet stands.)
When installing the printer, I choose native Brothers drivers. (If you install with Air-Print, then everything is exactly the same.)