There may be some interference between the two (DugiGuides & Pet Tracker addons) because DugiGuides has a module that covers Pet Tracking, though, no lua errors are showing, there still can be collisions in the background that could be causing this lag.
I found Pet Tracker did the exact same thing back in Cata (it clashed with DugiGuides), I stopped using Pet Tracker addon and used DugiGuides tracking instead 😉
As far as the new arrow, I love it but haven’t noticed anything with it yet, once work is complete I will try to spend more time in-game.