I've opened a 72dpi CS5 PSD in Photoshop 13.0.4 (Mac, 64-bit), and what's a 12pt is reported as a 23pt text in the dialogs.
Here's where it gets strange.
I open the very same document in Photoshop 13.0.1.1 (Windows, 32-bit) and the same piece of text is correctly reported as 12pt.
Here's where it gets stranger.
If I create a blank 72dpi document in Photoshop 13.0.4 on Mac and create a 23pt text, it's rendered at the correct size (over twice bigger than the first document I spoke about).
But if I drag this text into the problematic document on 13.0.4, it remains the same size, and it's still reported 23pt.
Let me take it slow here:
I end up with two very different size text layers in the same document. But they're still both reported as 23pt.
Again: in the same document. Two different size text. Both 23pt. I tried scaling the bigger one up a bit, with scale transform, to around 38pt. It displays as 38pt, but the text settings? They still show it as 23pt!
It's as if every text layer has its own invisible local DPI setting!
I opened this same PSD in Photoshop 13.0.1.1 on Windows, the two text fields are reported as different sizes: 37.72pt for the big one, 12pt for the small one (notice NEITHER of them is reported as 23pt on 13.0.1.1).
I open the just re-saved PSD back in Photoshop 13.0.4 on Mac, boom, they're back to 23pt, both of them.
It's. Complete. Nonsense.
I know you introduced Retina support with the 13.0.2+ versions and this hasn't happened on Windows, so that may be a possible source of the bug, but god knows.
Let me know where I can supply a test file for you.