In the sketch, you have applied Tangent constraints the wrong way. You should do it using method 2, by selecting endpoints.
http://www.freecadweb.org/wiki/index.ph ... angency.29
You applied coincident constraint first, then tangent between edges. While that often works, it causes poor solver convergence, and consequently tangency mismatch. I believe this is the cause for the loops in path, but I think there might be another bug involved.
Unfortunately, I can't recompute your Path project in v0.17dev which I'm using.
Traceback (most recent call last):
File "C:\_vt\dev\PC\Qt\FreeCAD\Default\Mod\Path\PathScripts\PathProfile.py", line 275, in execute
self.vertFeed = toolLoad.VertFeed.Value
<type 'exceptions.AttributeError'>: 'FeaturePython' object has no attribute 'VertFeed'
OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.8361 (Git)
Build type: Release
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.0.0