While using unicast mode and virtual mac address both boxes become a Master.

Config example:
hello-source-address 146.82.87.2
interface eth2
peer-address 146.82.87.3 #unicast mode
priority 200
rfc3768-compatibility #virtual mac address usage
virtual-address 146.82.87.1/24
vrid 1

Problem could be resolved with "vmac_xmit_base" directive in keepalived.conf (on the screenshot)

\https://manpages.debian.org/stretch/keepalived/keepalived.conf.5.en.html
\# Send/Recv VRRP messages from base interface instead of
\# VMAC interface
\vmac_xmit_base