Failure to retract occationally  

Failure to retract occationally

Things are working pretty good with 2.4.0 and really no major issues.  I did notice some stringing and looking at printing today I noticed the retraction doesn't always execute.  This is a multi-extruder/single hotend machine.  I have retraction set to 8mm and 40mm/s for retraction and deretraction speed.  Layers and tool change shouldn't matter with this issue since this happens on the same layer and tool.   "I do have retraction when tool is disabled" set to 0, but again I'm not certain this matters with my issue.  I don't enable z-lifting. All extruders have the same settings.  Layer height is set to 0.1mm.  I've attached a screen snapshot showing print head travel direction.  The stringing seen is due to the extruder not retraction prior to movement but notice in a few places retraction does occur.  I verified this by watching the print happen.

What could I look for to fix this?

Regards,

Steve