I found a reason ! :)  

In CatalogTree we manage if there is an error when the preview layer failed to load.

The `addXXX` methods  return a layer if it's succeeded and `undefined` if it's failed, if we add the `gaBrowserSniffer.mobile` test in the service the addXXX function always return `undefined` and the catalogTree wiil see that as an error but it's not.