Empty (invisible) extension icon

Our users have unstable problems with empty (invisible) extension icon both under Windows and OSX platforms (the extension is the same). This issue looks like this:
spExtensionEmptyIcon

I specify the default extension icon in the manifest.json file:
“browser_action”: {
“browser_style”: false,
“default_icon”: “skin/logo16-disabled.png”
},

Also according to the locked state of extension I dynamically change the icon using the chrome.browserAction.setIcon() API:
if (!this.IsLocked)
chrome.browserAction.setIcon({
path: {
‘16’: ‘skin/logo16.png’,
‘20’: ‘skin/logo20.png’,
‘32’: ‘skin/logo32.png’
}
});
else
chrome.browserAction.setIcon({
path: {
‘16’: ‘skin/logo16-disabled.png’,
‘20’: ‘skin/logo20-disabled.png’,
‘32’: ‘skin/logo32-disabled.png’,
}
});

The resources used for icon exists 100% in the “skin” folder of extension.

This bug is not stable, neither me nor our QA can’t reproduce it. As I said before only few of our users have this issue.

What could be the root of the issue?

Thanks for the help in advance,
Alex