Neola, this is a very well-known issue among high-end FFXIV players to the extent that some even go to third-party tools that directly rectify the issue described - and the problem goes away. While it's against forum rules to discuss third party or ToS breaking tools, there is a lot of research on this specific issue and it is completely game dependent. It is not ISP related. It is not "other software running on the computer" related. It is not FFXIV server related. That is a fact.