This traffic belongs to another routerboard, as I can block

I have installed a RB751U-2HnD with factory settings, which I manage with 30 users in a locality, in another locality I have installed two rb951g configured in mesh which work fine, rb751 has the ip 10.10.10.7/24 in wan, and the ip 10.10.10.2/24 rb951g in the wan, the problem is this traffic that consumes 751 rb reflected in the wan of 951g, the IP of the gateway is 10.10.10.1/24, I appreciate your help on this problem.