Hallelujah !

[NokNod]

After months of trouble shooting, I've finally found the setting in preferences that kills the audible glitches at the loop points when time stretching.

Preferences page / Customizations / Snap to Nearest Audio Zero Crossings. 

"Automatically snap edited audio clips to the nearest zero crossing of the waveform (the point at which there is no volume) to minimize glitches that can happen when waveforms are spliced together."  ? 

 

 

[scook]

If clips cannot be trimmed at zero crossings, a slight fade in/out should eliminate audio glitches at loop points.