Issues using multiple interfaces between two servers

[wireguard@meta-cti.com.br]

Hello guys, I'm having problems with my wireguard setup and I don't know
how to solve it. I have two computers running linux in remote locations.
One, which I will call computer A, is in a data center where we advertise
a block of IPs using BGP. The other computer is in a different location
and has two links connecting to the internet and with different providers.
I configured on computer A two wireguard tunnels with different keys and
ports. On computer B I did the same and added two routing tables, one for
each WAN interface and using the ip rule I created rules with destination
on two different IPs of computer A so that they leave through different
links.

As soon as I start the wireguard interfaces of both computers everything
works normally and I can ping both addresses from both tunnels. Then I use
the bird with OSPF and ECMP to take a subnet from the block that is
advertised on computer A to computer B. Everything works normally.

When I execute the wg command on computers A and B, I can see both IPs of
computer B's WAN interfaces in the tunnel's "peer" fields, one from each
remote WAN.

After some time working, it can vary from minutes to a few hours, suddenly
I see that both tunnels started to work on a single WAN interface of
computers A and B. If at this moment I execute the wg command on computer
A, I see that now the "peers" have the same address as only one of the WAN
interfaces of computers A and B, even with the routing rule forcing
packets to go out through different interfaces. Has anyone experienced a
similar problem and knows how it can be solved?

When I run the traceroute command on both computers A and B with the
destination address in the remote computer's WAN IPs, they actually come
out through the correct interface.