Thanks very much for testing this Mattias! The weird thing is that the difference is exactly the difference between 23.98fps and 24fps. I have tried to import the audio into a 24fps project and there it reads 01:28:49:17. So the length of the wav file is interpreted differently according to which frame rate the project has. There must be some way in which the wav file stores the fps information. Otherwise this does not make sense. Or there is some kind of other metadata in the wav file. Otherwise seconds should be seconds.
Best wishes,
Max