Duration wrong after importing to iTunes

I have a bunch of mp3 files that I want as a single file. From there I would export as an aac and import into iTunes and make it an audiobook.

When I combine the files in Audacity to a single track it shows the length as a 21:50:41 (twenty one hours and fifty minutes forty one seconds). This is correct. When I export as an aac and open it in VLC it show as the correct length.

The problem is when I import it into iTunes it shows as 784:44:43. I have remade the file multiple times but it always imports into iTunes like this. Any ideas?