unable to bind rdp socket

When I start rdp-backend on my Yocto imx8 system, I get these listings in syslog

# journalctl -b | grep rdp
Aug 31 13:08:05 iE250-0d02f9 weston[871]: [13:08:05.198] Command line: /usr/bin/weston --backend=rdp-backend.so --shell=fullscreen-shell.so --no-clients-resize --rdp-tls-cert=/var/keys/deif/rdp/server.crt --rdp-tls-key=/var/keys/deif/rdp/server.key
Aug 31 13:08:05 iE250-0d02f9 weston[871]: [13:08:05.208] Loading module '/usr/lib/libweston-10/rdp-backend.so'
Aug 31 13:08:05 iE250-0d02f9 weston[871]: [13:08:05.401] Registered plugin API 'weston_rdp_output_api_v1' of size 8
Aug 31 13:08:05 iE250-0d02f9 weston[871]: [13:08:05.401] Output 'rdp' using color profile: built-in default sRGB SDR profile
Aug 31 13:08:05 iE250-0d02f9 weston[871]: [13:08:05.401] Output 'rdp' enabled with head(s) rdp
Aug 31 13:08:05 iE250-0d02f9 weston[872]: [13:08:05.440] Command line: /usr/bin/weston --backend=rdp-backend.so --shell=fullscreen-shell.so --no-clients-resize --rdp-tls-cert=/var/keys/deif/rdp/server.crt --rdp-tls-key=/var/keys/deif/rdp/server.key
Aug 31 13:08:05 iE250-0d02f9 weston[872]: [13:08:05.441] Loading module '/usr/lib/libweston-10/rdp-backend.so'
Aug 31 13:08:05 iE250-0d02f9 weston[872]: [13:08:05.489] unable to bind rdp socket
Aug 31 13:08:05 iE250-0d02f9 weston[873]: [13:08:05.533] Command line: /usr/bin/weston --backend=rdp-backend.so --shell=fullscreen-shell.so --no-clients-resize --rdp-tls-cert=/var/keys/deif/rdp/server.crt --rdp-tls-key=/var/keys/deif/rdp/server.key
Aug 31 13:08:05 iE250-0d02f9 weston[873]: [13:08:05.534] Loading module '/usr/lib/libweston-10/rdp-backend.so'
Aug 31 13:08:05 iE250-0d02f9 weston[873]: [13:08:05.545] unable to bind rdp socket

What I can see it that weston forks twice, and these two forks each tries to start RDP, but only the parent succeeds on this.
I assume that "unable to bind rdp socket" is ignorable.