Text layers in Photoshop will auto-update the layer name with the text content of the layer unless you manually edit the layer name in the layers panel. Then it retains the manually entered layer name. How would one go about restoring this auto-updating of the layer name to a layer whose name has been manually edited?
Rename is sticky. It relates to the internal data structures that Photoshop is using and how these things are represented. Once you've named the layer, it's no longer, um, virgin text, and there's no way back. (Every possible extension of that metaphor is accurate but ranges from risque to crude, so I'll leave it at that.)