pcbnew: interactive router setting: "Optimize pad connection" leads to strange effects.

Description

please obeserve the upper track, if "Optimize pad connection" is active.

2021-04-29-12-48-58

Steps to reproduce

KiCad Version

Application: KiCad PCB Editor

Version: (5.99.0-10428-g50fd94d35d), release build

Libraries:
	wxWidgets 3.1.4

Platform: Windows 10 (build 19041), 64-bit edition, 64 bit, Little endian, wxMSW

	wxWidgets: 3.1.4 (wchar_t,STL containers)
	Boost: 1.75.0
	OCC: 7.5.0
	Curl: 7.74.0-DEV
	ngspice: 34
	Compiler: Visual C++ 1928 without C++ ABI

Build settings:
	KICAD_SCRIPTING=ON
	KICAD_SCRIPTING_MODULES=ON
	KICAD_SCRIPTING_PYTHON3=ON
	KICAD_SCRIPTING_WXPYTHON=ON
	KICAD_SCRIPTING_WXPYTHON_PHOENIX=ON
	KICAD_SCRIPTING_ACTION_MENU=ON
	KICAD_USE_OCC=ON
	KICAD_SPICE=ON