Hanging/running on spot occasionally

Happens during raids intermittently, i.e., not enough to give off any blatant perpetrator. My MS is low, no packet loss, but I'll occasionally see people running on the spot, 'frozen', then it will go back to normal.

I use the HD client but without WOD models, i.e., I keep them turned off. Vulkan d3d9 as well as the usual addons (Weakaura/DBM/Skada).

Noticed this more as of late - never used to experience this. Fairly sure my internet isn't the issue.

Any advice welcome!