Sorry I did want to get back to this but I got a bit sidetracked.

Basically it's been happening since Heavensward. I found it most notable when I teleport into Idyllshire. It'll either lock up for a long time or lock up briefly. The instance thing is rare and it happens briefly with New Gridania.

These are my system specs if it helps and I use the Steam version.

AMD FX 6300 CPU
8GB ram.
Nvidia Geforce GTX 1050
Windows 10 Home.