domain = {{ pihole_domain }} rendered as an unquoted bareword containing
a dot (e.g. "pi.hole"), which is invalid TOML. TOML parsing is
all-or-nothing, not line-by-line, so pihole-FTL rejected the entire
config file on that one line and silently fell back to its compiled-in
defaults — including binding its webserver directly to ports 80/443.
That collided with caddy, which wants the same ports, causing caddy to
crash-loop and get reported as "changed" (needing a restart) on every
subsequent ansible run.

Quoting the domain value lets the file parse successfully, which in turn
surfaces a second, previously-unreachable bug: the custom webserver port
(pihole_port) was rendered as a bare number, but Pi-hole v6 FTL requires
each listener address to carry a trailing flag character (o = optional,
s = TLS). Without it FTL rejects the value the same way and reverts to
the 80/443 default. Appending "o" fixes that.

Both bugs had to be fixed together: the quoting bug was blocking the
parser from ever reaching the port line, so the port fix alone had no
effect until parsing succeeded end-to-end.

Co-Authored-By: Claude.ai