Crackling monitoring issue wavelab LE

I have an issue: monitoring audio playback in WLab LE - it sounds very much like a scratchy record.
MacBook Air 13inch early 2015 OS 11.7.10 BigSur 1.6GHZ dual-core I5 8GB 1600MHz DDR3 ram.
Brand new fresh install, WaveLab LE 11.2.0 build 13 x64, 100% default settings.
Listening to a file play in WLab on headphones on built-in headphone output sounds like a scratchy record. File sounds clean when played in phones using any other playback tool: Quicktime, Audacity, WavePad, & directly from the OS; also playback from WLab via outboard sound device sounds fine (MOTU M4, Presonus AudioBox iOne). File rendered from WLab sounds fine played with any of the above methods (except opened within WLab itself using built in headphone).
I’m confused. Any thoughts (other than just don’t use the headphone output) ?


Try raise Buffers settings in Audio Device

regards S-EH