i dont know how to find the error report you may want so you may have to tell me but i have tried uninstalling and reinstalling the add on as well as reset defaults and nothing works my pet bar for my mage is gone but all other toons have it

My mage's water elemental is equally lonely and without a way to be commanded.
My shaman is also lacking a pet control bar.
My hunter's pet bar was still on screen, though offset. My warlock's and DK's pet bar were also present.

I don't know if it's related but on logging in with the 5.4.0 version, bar 2, 3, 4, 5, 6 are skewed away from where I had them, and bar 7 is missing. Previously those bars were all stacked one above (vertically) the other using Sticky Bars. 4 is still above 2 (so the relative x position is the same). 6 is still stuck to 5, but the others were no longer attached to one another.

9 and 10 were still where I put them.

The Class bar (stances) and vehicle dismount button were also off.

I will test again on Tuesday next.

Are you running the 5.4.0 version on the PTR? If not, then that could explain issues.