Hi, I've been having this extremely annoying issue where I disconnect with a 90002 error upon the phase transition to Golden Bahamut in Ultimate Coil. This has happened on roughly 60% of my runs so far.
Just today, I have disconnected there twice, at 9:04PM and 9:33PM EST (December 13). There were many others before this, but I don't remember the exact times.
I also sometimes will disconnect upon resetting an instance (after a wipe), leaving an instance, or teleporting to a housing zone, but not as frequently.

some specs:
Windows 8.1
Ethernet connection
ISP is Spectrum
Modem: ARRIS TG1672G
GPU: GTX 770
CPU: i5-4670
8GB memory

I have tried the following things, yet still encounter this disconnect issue:
Reinstalling ffxiv
Reinstalling ffxiv on a new SSD
Reinstalling my graphics driver - clean reinstall after using Display Driver Uninstaller
Playing on the lowest possible graphics settings
Playing without VPN (I normally have it on)
Playing with DX9 (normally DX11)
Resetting internet modem
Scanning for viruses - none found
Checking for memory issues - 0 errors (Windows memory diagnostic)
Checking for GPU memory issues - 0 errors (Video Memory stress Test)
GPU/CPU health look good

I don't believe this to be a connection issue, as I have otherwise no lag or disconnections; the only time I disconnect is under these specific instances. I haven't had any noticeable graphics issues in this game or any other either. But, this has been an aggravating issue since I am slowing down my group's progression due to these disconnects 14 minutes into the fight.

Any ideas on what could be the issue or how to diagnose it?