I had my pets ordered, realised that one of them was out of place, and went to Custom Ordering. My pets have now apparently randomly re-ordered themselves. Is this supposed to happen? Is it related to ID numbers? I thought the order would stay the same; instead of moving one pet, I now have to move them all.

did you click 'custom' on the pet ordering page? that will arrange the pets in whatever order you last saved as custom.

Yes, I clicked that button. I don't remember ever ordering them in the order they ended up in.

I'd since reordered my pets into the order I wanted them in, alphabetic in their groups, then tried it again. (Forgot to take a screenshot of the page as they were before, but here's my dropdown menu.)

Here's how they ended up.

well once you've confirmed the order you want them to stay in, you should also click 'save as custom' so if you ever need to quickly get them back in that order again, you can just click 'custom' at the top of the page and it'll do so.

If you had no custom order saved it will default to whatever order it's doing now. What you need to do is place them in the order you want them in (again, I know), scroll all the way to the bottom of the page, then click "Order Pets". If you want to save the custom ordering so your top custom button will work, use that "Save as custom" button.

Maybe that should be added to the text at the top - something like "to save Custom Orders, make sure to click 'Save As Custom' or they'll go random when you try to Custom Sort them again"? Because I've never seen that button before - when I scroll down to click 'Order Pets' the gap for the 'or' shoves it off my screen and I never had a reason to scroll down any further.

I didn't know what the button did, so I clicked it without doing anything. It did not remain how I left it. That is to say there's a cache delay and it looked like it remained as I lieft it to start with but then it went random after a cache delay. On the odd chance that somehow somewhen I did make a Custom Order and that's what was going on, i tried loading the Custom Order. No effect