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.
/**
 * Functionality for communicating with Tor.
 */
#ifndef BITCOIN_TORCONTROL_H
#define BITCOIN_TORCONTROL_H
extern const std::string DEFAULT_TOR_CONTROL;
static const bool DEFAULT_LISTEN_ONION = true;
void StartTorControl();
void InterruptTorControl();
void StopTorControl();
#endif