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 <miner.h>
#include <net.h>
#include <net_permissions.h>
#include <net_processing.h>
#include <netbase.h>
#include <node/context.h>
#include <node/ui_interface.h>
#include <policy/feerate.h>
#include <policy/fees.h>
#include <policy/policy.h>
#include <policy/settings.h>
#include <protocol.h>
#include <rpc/blockchain.h>
#include <rpc/register.h>
#include <rpc/server.h>
#include <rpc/util.h>
#include <scheduler.h>
#include <script/sigcache.h>
#include <script/standard.h>
#include <shutdown.h>
#include <sync.h>
#include <timedata.h>
#include <torcontrol.h>
#include <txdb.h>
#include <txmempool.h>
#include <util/asmap.h>
#include <util/check.h>
#include <util/moneystr.h>
#include <util/string.h>
#include <util/system.h>