Tor Browser 6.5a4 is ignoring additional SocksPorts
Let's assume you have something like that in your torrc-defaults file in Tor Browser:
SocksPort 9150 IPv6Traffic PreferIPv6 KeepAliveIsolateSOCKSAuth
SocksPort 9160 IPv6Traffic PreferIPv6 KeepAliveIsolateSOCKSAuth
And let's say you point your Torbirdy to 9160. That setup works perfectly fine with Tor Browser 6.5a3 and breaks with 6.5a4. Setting
false (trying to simulate the old behavior) does not fix it. Nor does setting
TOR_SOCKS_PORT=9150 help. In fact, looking at the code it seems this is not supported anymore which we should fix.