https://github.com/bitcoin/bitcoin/blob/d72758c3f6c34cd835f5de3efc230964f3b1ea56/src/torcontrol.cpp#L539

If a user is running Tor proxy outside localhost (perhaps on other host inside LAN or in containerised environment) , the automatic creation of onion services ends up creating an onion service listening to hardcored 127.0.0.1 address on the Tor proxy's host instead of the private address of the bitcoind – effectively running an empty onion service listening the Tor proxy's localhost.
#include <chainparams.h>
#include <torcontrol.h>
#include <util/strencodings.h>
#include <netbase.h>
#include <net.h>
#include <util/system.h>
#include <crypto/hmac_sha256.h>
#include <vector>
#include <deque>
#include <set>
#include <stdlib.h>
#include <boost/signals2/signal.hpp>
#include <boost/algorithm/string/split.hpp>
#include <boost/algorithm/string/classification.hpp>
#include <boost/algorithm/string/replace.hpp>
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/util.h>