I cannot reproduce. I've tried on Ubuntu 16.04

I can reproduce on every version starting 1.14 through current, even 1.19.0-insider.
B.t.w, are you implying that Visual Studio Code only runs on Ubuntu and not Linux?

@Pok-Pok I am saying I cannot reproduce on my installation of Ubuntu 16.04. Can you please provide more information for me to try to reproduce, such as what is your distro, what customizations you have done to VS Code, etc.

I use Slackware64 14.2, latest patches.
I installed a single plug-in into VSCode: ESLint, but it is disables.
Other than that I have the following options set:

// Place your settings in this file to overwrite the default settings
{
	"editor.detectIndentation": false,
	"editor.fontFamily": "'Courier New', 'Droid Sans Mono', 'Courier New'",
	"editor.fontSize": 11,
	"editor.formatOnSave": false,
	"editor.insertSpaces": false,
	"editor.tabSize": 6,
	"terminal.integrated.fontSize": 9,
	"window.zoomLevel": 0,
	"workbench.colorTheme": "Default Light+",
	"workbench.iconTheme": "material-icon-theme",

	"javascript.format.insertSpaceAfterConstructor": true,
	"javascript.format.placeOpenBraceOnNewLineForFunctions": true,

	"typescript.check.npmIsInstalled": false,
	"typescript.format.insertSpaceBeforeFunctionParenthesis": true,
	"typescript.format.placeOpenBraceOnNewLineForFunctions": true,

	"javascript.format.insertSpaceBeforeFunctionParenthesis": true
}

That is all I have customized.

In the mean-time I have found that this is not confined to one font (Courier New); it also manifests itself with Droid Sans Mono, only the effect is much smaller: it requires a lot more braces on the same line for the effect to be noticeable.

I can reproduce with the following settings:

{
    "editor.fontFamily": "Hack",
    "editor.fontSize": 16,
    "editor.lineHeight": 25,
    "editor.renderWhitespace": "boundary",
    "workbench.colorTheme": "Quiet Light"
}

The font and the theme settings are relevant because the theme ends up in the creation of many distinct color regions (each character gets a different color) with the following snippet:

var arr = [

    ['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x'],['x']

]

When changing the file-type to .txt, there is no such problem (the number of spans is reduced). I believe it must be some sort of rounding error in Chromium, where each span holds in a lossy way its width.