"Webview: Cannot load resource outside of protocol root", if .md source is an network share

[SebastianBaeumler]

if a markdown file is located on a network share, images ![test](./2019-10-30-10-04-55.png) can not be loaded in preview.
Same folder on the local filesystem work fine.

Console display the error

webviewProtocols.ts:27 Webview: Cannot load resource outside of protocol root

e.session.protocol.registerBufferProtocol	@	webviewProtocols.ts:27
	async function (async)
	e.session.protocol.registerBufferProtocol	@
	apply	@
	handleMessage	@
	ipcRenderer.on.args	@
	emit	@

Version: 1.39.2 (user setup)
Commit: 6ab5985
Date: 2019-10-15T15:35:18.241Z
Electron: 4.2.10
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Windows_NT x64 10.0.17134

Steps to Reproduce:

1. create a markdown file with images on a network share.
2. markdown file and image are in the same notwork folder.
3. open preview

Does this issue occur when all extensions are disabled?: Yes