A TECHSUPPORT file is a compressed volume. When the support agent receives it, it needs to be uncompressed. It is during this process that it will flag an error if the file was corrupt.
A simple test that you can perform is to try to uncompressed it prior to sending it. The usual error we see is "FILE IS BROKEN".
Please note, if during the transfer from the WING device, you see any error reported, the result is probably a defective file