The short of it: sometimes my Bear pet, as a Warden, is simply just gone and I must re-summon him repeatedly every few minutes.
Things I'm aware of: I understand a few things can cause this such as going to a different timeline as part of a quest, changing outfits under certain circumstances, entering some zones seem to do this, and a few other things.
This bug is not related to "Things I'm aware of," above, this bug is solely about running around in a zone and the pet is simply just disappeared for unknown reasons. Is it lag? Is it pathing? Is he humping a tree somewhere? Am I blinking in and out of existence?
May be important: Most sessions this does not occure (as in, never) and then some sessions this is constantly happening repeatedly and every third encounter I have to re-summon my bear, and lastly I have never seen my bear die in combat or even have its health reduced below 90%. The bear is not dying.
My buff panel is hidden so I'm not accidentally right click the icon and shutting off the spell/summon.