I've tried turning off all background applications for a few runs on golden and it didn't change the DC's. The only one I haven't tried turning off is discord, but that one is required for high-end raiding. I also do not play with the overlay on discord, so that isn't a problem. I'd like to note that I also DC when moving zones via teleport (during the black load screen with the zone name), or entering/leaving a duty sometimes. This phoenix DC bug might be related to disconnects when moving characters around the instance servers possibly? The theory I have is that because this is the first mechanic that actually kills you on purpose and doesn't reset instance, that when you do "die" in this phase, phoenix "revives" you by moving your instance server to the "golden bahamut" server. This instance move might be what is disconnecting people.