I have recently switched to using firmware retraction in Marlin, which allows the prime and suck distances to have independent speeds and to be fine tuned mid-print. KISSlicer has an option to enable this in Printer -> Firmware -> Mark Path Start/Stop -> G10/11, so I though I would try it out. However I was surprised to find that KISSlicer seems to issue these commands *every* time the extruder stops/starts, rather than only those times when destring would be triggered. That is, it ignores the destring Min Jump and Trigger parameters, and results in more retractions than are needed.
I guess it probably isn't quite right to call the current behaviour a bug but it would seem to make more sense if firmware retractions were able to follow those trigger settings. Perhaps this could be considered a request for enhancement for 1.5+ :-)