@Jarosław-Narbut What do you mean by "changing resistors" as they already exists... what values do you propose??
Anyway, when I've replace node that used SW for serial communication with HW one, the problem is gone.
R5 and R6 change or add to 10k.
I have 11 nodes with SW serial, 1 with HW, and GW mqtt with HW. RS485 speed set to 57600kbps.