[Solved] Bug? PrusaSlicer not retracting and not zeroing out extruder at layer change but only every other layer???  

Bug? PrusaSlicer not retracting and not zeroing out extruder at layer change but only every other layer???

Strange issue I've run into today trying to print a small simple part using PrusaSlicer 2.7.2.  During the first few layers I started noticing massive under extrusion, watching the printer closer I realized that every other layer the printer would do this weird slow movement at the layer change and retract a massive amount (~30mm).  This only occurred at the bottom 7 layers that contain solid infill, above which it's just perimeter walls and that part printed perfectly fine.

Looking at the code I realized that every other layer change (for the first 7 layers starting at layer 3) the slicer does not do its normal retraction and zero out the extruder but skips those lines, moves to start of the next layer, skips the normal detraction as well before starting the next layer.  Since the extruder was not zeroed the but the first line of the next layer acts as if it was this causes the extruder to retract nearly the entirety of the filament used in the previous layer.

This is the first time I've run into something like having had dozens of successful prints using the same slicer settings, it only reared it head on this specific model.  I haven't had much luck finding someone else with the same issue. Hopefully someone knows what's going on.

Here are some screenshots of the slicer code at the two layers.

Layer 3, (Bad layer change gcode):

Layer 4, (Correct layer change gcode):

Any help would be appreciated, thanks.

After writing all that I was messing with the slicer settings and found that if I disable ramping lift or change slope angle to zero the layer change gcode is corrected.  So in the end not a huge deal as I can leave that off for this model, but a really strange bug nonetheless.