Transform effect vanished from Appearance Panel. Multiple times
After using Distort & Transform/Transform from the Appearance Panel, I noticed that this effect was missing from the list of effects that I'd used. As you can see in the attached image, Transform is not in the list. The long shadow on this text is created using that effect and it is still live, but there's no way to edit it since it is not showing up in the Appearance Panel. I started over and created it once more and once again, it wasn't in the panel. I tried a 3rd time and it worked as expected.
Egor Chistyakov commented
The blue stroke item in Appearance is collapsed (the arrow before the 'Stroke' facing right). Try to expand it and you could see the effect applied to it.