Ok…weird.
When We bring an audio file into AE, the duration listed of the file is wrong.
In the screenshot attached, the audio file is 4secs, 11 frames.
The project windows says it’s 5 seconds long(?).
The Media and and out imply 4 seconds long (??)
But if we make a comp of the audio file, the Project windows display’s the comps duration correctly.

Nothing wrong or odd with the kHz settings, bit rate or frame rate - as far as I can tell.
Brought the same audio file into Premiere, and the Project window in PP is correct.