When DNS times out, "dig +short" can emit ";; communications error to
SERVER#53: timed out" to stdout (not just stderr). resolve_gw's
grep -m1 '[0-9]' would accept that line as an "IP" (it contains
"10#53"); gw_monitor_tag would carry it through sed and produce a
multi-line tag. The latter ended up as state directory names like
"gw-;; communications error to ...\\nikev2.hetzner.v6/".

Wrap dig in 2>/dev/null and filter "^;" diagnostics; in gw_monitor_tag
also take only the first PTR line.