192khz interchange problem

Well, there's no LF cut that I can measure, but in the second clip, all the audio is indeed cut off abruptly at 4kHz. And yes this is likely to sound somewhat 'muffled'...

What you actually have is this:

If you look at the red circle on the right, you'll see what you've effectively lost.

Sampling on a Zoom F4 at 192k is nothing more than a significant waste of memory space. None of the audio you've recorded even makes it up to 20kHz, never mind the 96kHz you'd need to justify that sample rate. Leaving aside any other considerations, the Zoom's mics won't record at that sort of frequency, and adult human hearing only extends to about 15kHz! So 3/4 of the file you've recorded is noise - nothing more, nothing less.

I'm afraid that I don't know what the audio interchange is doing, but to get you out of trouble, I can tell you what the best way to deal with the 192k audio is - and that's to import it into Audition separately and sample-convert it to 48k there. I can absolutely guarantee that you will lose nothing of your audio at all doing it that way; Audition is independently verified as being about the best sample converter there is. Put the files back into Premiere, and you should then need no further conversions at all.