There shouldn't be a size limit. However only one audio file can be imported per slide.
Are you trying to import the full 58 minutes of audio on to a single slide?
Are you using the Import Audio function in Presenter?
I import it at slide 1 using the import audio function in the presenter ribbon in PowerPoint, and then move the slide and animation markers of the remaining 51 sildes to have it synchronize with the slides and animations across the entire presentation. But at around 10 minutes it repeats the first 10 minutes, and so on until the end of the presentation.
Only this 1 audio file is inserted.
I would try breaking the audio file up into different pieces. One for each slide if you can, or maybe just split it into 6-10 and then do the rest of the association in Presenter. If that solves the problem, then you may have identified a bug.
You should be able to use something like Audacity (free) to split the audio up.
I ended up using Articulate presenter, as I had a deadline and didn't want the extra steps of breaking up the audio (I have software to do so but not the time). I will try your suggestion in the next few days.