edit clip in adobe audition. PCM decoding incomplete

I'm using latest builds of Prem pro and Audition (25.6.3 and 25.6) on windows 11 (build 26100)
When I click on "edit clip in audition" , audition opens up and begins decoding my Wav file PCM but gives up halfway through giving me silence.
This is a workflow and a recording device that I've been using for years. This problem only reared it's head for the first time last week.
Files a a waveform audio from a Zoom H6. prem media file properties lists it as "Source Audio Format: 96000 Hz - 24-bit - Mono"audition only processes first few mins of PCM

PC: Intel i9-10900k, 120gb ddr4,Nvidia Rtx3080, programmes on NVME, cache on ssd, footage on RAID HDD

Any help would be welcome as I usually prefer to use auditions tools than prem pro for clean-up and dynamics