Is collectd-prometheus only working with IPv6 ?

Hello,

I have installed collectd-prometheus-5.8.1p3 on OpenBSD 7.2-STABLE/amd64
and collectd-prometheus-5.12.0p0 on OPenBSD 7.2-CURRENT/arm64. I added
the following to my /etc/collectd.conf:
<Plugin "write_prometheus">
Port 9103
</Plugin>

In both case, the webserver only listens on IPv6, not IPv4.
# netstat -na | grep 9103
tcp6 0 0 *.9103 *.* LISTEN

I have tried setting a "Host" parameter but that has no effects.

Is this known / expected?
Is there a way to listen on the IPv4 addresses?

Thank you,
Joel C.