For context, this is a 1.14 multiplayer server, unmodified, fairly new, only played on by me, my girlfriend, and her niece. No known issues with it.
Last night my girlfriend and I explored to a faraway mesa and ice biome, and because we'd tamed wolves along the way and we kept having issues with them not always following/teleporting to us right, I decided to teleport us all home ("/tp @e[x=7944,y=70,z=-3742,distance=..30] 592 70 241"-- I've had no problem teleporting users with their animals like this before). The game's console reported having teleported 5 entities (the two of us, the two dogs, and a nearby rabbit), but only my girlfriend and I showed up at the spot we teleported to. We teleported back and the dogs weren't there either. I checked the server console afterward and found these errors about the animals(?) apparently being at the wrong location. I teleported myself to (37,15) and it was fine, but no dogs were there. I teleported myself to (497, -234)... and the terrain looked the same as (37,15) except that I was immobile and vibrating. So I teleported myself back to our base. Today, I walked on foot to both sets of coordinates and both were visibly different areas and seemed fine, no chunk errors, but also no dogs. I really have no idea what happened here.
I'm not as worried about the specific dogs (though I am annoyed to lose them after all our efforts to keep them safe) because they can be replaced, but I want to understand what happened so I can avoid it happening again. Both dogs are named ("Jidave" and "Big Meat Pete"). I tried various attempts to teleport Jidave by name and it always said "Entity not found", but of course if the dog still exists, it's probably in an unloaded chunk anyway. I've tried searching for them in NBTExplorer, but I don't think I know how to use that search properly (anyone know what I should put in the Name and Value fields?). Anyway, does anyone know what happened with this error? Thanks in advance.