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.
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <net.h>
#include <banman.h>
#include <clientversion.h>
#include <consensus/consensus.h>
#include <crypto/sha256.h>
#include <net_permissions.h>
#include <netbase.h>
#include <node/ui_interface.h>
#include <protocol.h>
#include <random.h>
#include <scheduler.h>
#include <util/strencodings.h>
#include <util/translation.h>
#ifdef WIN32
#include <string.h>
#else
#include <fcntl.h>
#endif
#ifdef USE_POLL
#include <poll.h>
#endif
#ifdef USE_UPNP