Creepage DRC completely stops working if PCB has malformed edge

I'm not sure if something can be done about this, but it can lead to false negatives, which is highly undesirable. If it can't be fixed, please add warning to the docs that creepage DRC requires valid board edge to work properly.

Steps to reproduce

  1. Open PCB from this project:

    Malformed edge creepage test.zip

  2. Notice there is an extra line in Edge.Cuts which causes malfomed board edge.

  3. Run DRC. Observe that no creepage violations are reported.

  4. Delete the line.

  5. Run DRC again. Observe that 3 creepage violations suddenly appear.

Malformed edge location.png

KiCad Version 

Application: KiCad x64 on x64

Version: 10.99.0-176-g1605470467, release build

Libraries:
	wxWidgets 3.3.2 
	FreeType 2.13.3
	HarfBuzz 12.3.0
	FontConfig 2.17.1

Platform: Windows 10 (build 19045), 64-bit edition, 64 bit, Little endian, wxMSW
OpenGL: ATI Technologies Inc., AMD Radeon RX 7900 XT, 4.6.0 Compatibility Profile Context 25.6.1.250522

	wxWidgets: 3.3.2 (wchar_t,STL containers)
	Boost: 1.90.0
	OCC: 7.9.2
	Curl: 8.18.0
	ngspice: 45.2
	Compiler: Visual C++ 1944 without C++ ABI
	KICAD_IPC_API=ON
	KICAD_USE_PCH=OFF

Locale: 
	Lang: en_GB
	Enc: UTF-8
	Num: 1,234.5
	Encoded кΩ丈: D0BACEA9E4B888 (sys), D0BACEA9E4B888 (utf8)