Good afternoon and thank you for posting on the Final Fantasy XIV Technical Support Forums.

To help narrow down what may be causing this, I'd like to ask a few questions regarding the issue.

1) How frequent is the issue? Does it happen everywhere or only in select locations/instances?
2) Do you notice any other issues besides audio lag?
3) What is your sound setup like? Are you running the audio through HDMI, USB speakers, 3.5mm jack, DAC, etc?
4) Does changing the audio output have any affect on the issue?
5) Please list everything you have tried so far to alleviate the issue.

We hope we can be of assistance in helping you enjoy the exciting world of Final Fantasy XIV!