I agree that it’s probably a frame rate issue:
Dividing the longer file in seconds (incorrectly rounded) by the shorter; 5329/5324=1.0009
Dividing 24/23.98=1.0008
So that’s a pretty close value, roughly rounded, and not accounting for just how these frames are allocated specifically (because I just don’t know). But it’s certainly closer than 48/44.1=1.088.
If you are in Nuendo and select import audio and navigate to the exported file and select it (but don’t import it), does it give you the longer duration or the shorter? Just trying to figure out if there could be a problem with how the other programs measure the file rather than Nuendo…
And lastly, if you pick a different non-compressed file format, does the length still vary?