killer traffic (not big, but paralytic)

Hi

I’ve strange problem in my network with main router RB433.

After disconnecting from LAN some distant device, what is NOT directly connected to main router, starts continious traffic (0.5~1mbit). Routeros v4.22, upgraded v5.11.

*Traffic mostly comes from a disconnected device to main router (0.5mbit)
then it is screemed back (further) to other wlan and lan devices connected to main router (making traffic 0.5mbitN_devices, connected to nat router).

*The only possibility to get situation better is either to reboot main router, either vlan disable/enable

How to solve?
Janis

ps. Traffic comes mostly from 192.168.7.35 AFTER IT IS DISCONNECTED or rebooted.
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