Traffic does not reach the second virtual router with assimetric routing, problem in linux bridge?

Question

linux

There are two physical servers (1 and 2) having a common local network, they act as virtualization hosts with KVM + QEMU. Virtual routers (Mikrotik - M1 and M2) work on each of these servers, with two interfaces, one to the local network, the second to the Internet to the provider, tap interfaces are connected via bridge-utils. On the M1, the default gateway for the LAN. On each of the routers, a tunnel was raised to a remote office.
If on M1, the tunnel to the remote router falls, routes are rebuilt and traffic goes through M1 to M2 and into the tunnel to the remote office, everything is the same at the remote office, there are no problems with routing.
But the virtual machines on server 2 are not available from the remote office, since the traffic goes to them directly through M2, and returns through M1. On server 1, all virtual machines are available. when tcpdump -i tap2 - M1 interface on the virtualization host icmp replies do not come to it, although tcpdump -i br1 - bridge on the same server, shows that icmp replies reach the server. The virtual machines themselves receive traffic and send a response, which is lost on server 1.
From the virtual machines on server 2, the ping reaches the remote office, but tcp syn does not come.
In my opinion, the problem lies somewhere in the bridge-utils. In virtual labs, the problem is not reproduced, there is no way to try ovs yet. vrrp is raised between routers, so it's impossible to solve everything by routing.