According to the confluence link below, I do not think that it matters as long as at least one of the legs is in an answered state.

https://freeswitch.org/confluence/display/FREESWITCH/mod_commands#mod_commands-uuid_bridge

From: FreeSWITCH-users <freeswitch-users-bounces@lists.freeswitch.org> On Behalf Of Mody, Darshan (Darshan)
Sent: Monday, November 12, 2018 1:48 AM
To: FreeSWITCH Users Help <freeswitch-users@lists.freeswitch.org>
Subject: [Freeswitch-users] What is the recommended practice to use uuid_bridge?

Hi

We have a FS which receives inbound calls (IB). Using FS’s ESL we originate outbound calls (OB). We want to bridge the media of inbound to outbound calls.

Should we be using uuid_bridge command with arguments IB and OB (uuid_bridge IB OB) or should we be using (uuid_bridge OB IB).

Thanks

Darshan