Distortion during playback from large files or high bitrate WAV's

Hi,

Im seeing some new behaviour during playback on my main studio computer of large or high bitrate files since the upgrade to 6.5.3 that is causing some distortion. It appears similar to an insufficient buffer size, although I've tried increasing to the maximum with no effect. 

The waveforms are also visibly slow to load in the GUI during playback for large files such as a mix. Pausing the playback momentarily, to allow the file to load seems to stop the distortion but the same files play perfectly in other dj software/audio apps and also when exported to a USB for use in a CDJ. 

Any help would be appreciated.

System details:

Mac Pro (Late 2013) - Big Sur 11.5.2

2.7 GHz 12-Core Intel Xeon E5

128 GB 1066 MHz DDR3

Internal SSD