I downloaded full GSX installer, uninstalled GSX and then reinstalled. Issue gone.
That's to be expected, since the full installer always contains everything updated to the day but, it would haven been fixed just the same if you downloaded the vehicle updater installer as I've said, since it was newer than the one you said you downloaded.
The website description of the vehicle says "Contains all vehicles released
after: June 1st, 2016".
It doesn't mean the file update date
is June 1st, it means it contains every vehicle that has been updated AFTER that date, so it's constantly updated and is related to what is contained in the FULL GSX installer so, since the GSX Full installer has an update date of June 14th (this IS an "update date" instead), the download link for the vehicles contains a link to an installer that keep changing, to contain whatever vehicles has been updated FROM the date that says "after" TO the date of the GSX FULL installer.