Reload fails: "tsnet: listener already open for tailscale, :80"

The usual systemd unit for caddy includes an ExecReload= option:

ExecReload=/usr/bin/caddy reload --config /etc/caddy/Caddyfile --force

When this is run on a caddy service that already connected to Tailscale, we get this error: loading config: loading new config: http app module: start: listening on tailscale/nitter:80: tsnet: listener already open for tailscale, :80

Dec 26 21:10:05 hydrangea systemd[1]: Reloading Caddy.
Dec 26 21:10:05 hydrangea caddy[2407]: {"level":"info","ts":1672089005.6320755,"msg":"using provided configuration","config_file":"/etc/caddy/Caddyfile","config_adapter":""}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"info","ts":1672089005.6348317,"logger":"admin.api","msg":"received request","method":"POST","host":"localhost:2019","uri":"/load","remote_ip":"127.0.0.1","remote_port":"40046","headers":{"Accept-Encoding":["gzip"],"Content-Length":["203"],"Content-Type":["application/json"],"Origin":["http://localhost:2019"],"User-Agent":["Go-http-client/1.1"]}}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"info","ts":1672089005.6360798,"logger":"admin","msg":"admin endpoint started","address":"localhost:2019","enforce_origin":false,"origins":["//localhost:2019","//[::1]:2019","//127.0.0.1:2019"]}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"warn","ts":1672089005.6363716,"logger":"http","msg":"server is listening only on the HTTP port, so no automatic HTTPS will be applied to this server","server_name":"srv0","http_port":80}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"info","ts":1672089005.636495,"logger":"tls.cache.maintenance","msg":"started background certificate maintenance","cache":"0xc000354a10"}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"info","ts":1672089005.63655,"logger":"tls.cache.maintenance","msg":"stopped background certificate maintenance","cache":"0xc000354a10"}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"error","ts":1672089005.6366794,"logger":"admin.api","msg":"request error","error":"loading config: loading new config: http app module: start: listening on tailscale/nitter:80: tsnet: listener already open for tailscale, :80","status_code":400}
Dec 26 21:10:05 hydrangea caddy[2407]: Error: sending configuration to instance: caddy responded with error: HTTP 400: {"error":"loading config: loading new config: http app module: start: listening on tailscale/nitter:80: tsnet: listener already open for tailscale, :80"}
Dec 26 21:10:05 hydrangea caddy[2031]: {"level":"info","ts":1672089005.6377842,"logger":"admin","msg":"stopped previous server","address":"localhost:2019"}
Dec 26 21:10:05 hydrangea systemd[1]: caddy.service: Control process exited, code=exited, status=1/FAILURE
Dec 26 21:11:35 hydrangea systemd[1]: caddy.service: Reload operation timed out. Killing reload process.

Restarting the service works fine, as expected.

{
        admin localhost:2019
        email iliana@buttslol.net
}

(global) {
        encode zstd gzip
        handle_errors {
                respond "{http.error.status_code} {http.error.status_text}"
        }
        header cache-control "public, max-age=0, must-revalidate"
        log {
                output file /var/log/caddy/access.log
        }
}

:80 {
        bind tailscale/nitter
        respond / "butts"
}

Start by reproducing the systemd ExecReload command with the provided Caddyfile, then trace Caddy's admin /load entry point and the Tailscale listener lifecycle. Compare reload behavior with a full service restart; done means configuration reload succeeds without the existing tailscale/nitter:80 listener error or timeout.