Why might an Animation play fine in the Editor but not on an iPad?

I have an animation which is working fine in the editor, but doesn't appear to be playing when I deploy to an iPad.

It is very similar to another animation which is working fine on another screen.

These are simple legacy animations in my GUI (picking up sprites, moving and resizing them).

Yes, I have checked for rogue "#if UNITY_EDITOR"s!

I'm quite experienced with Unity but new to working with IOS.

Can anyone think of kinds of things that I might look for here - whether it's things that might cause things to only work in the editor, or to not work in IOS?