That is not a reliable metric. There is any number of reasons why your disk could have been cluttered at roughly the same time. And a download is usually written on disk as a temporary file. That the space is used up, even if the download fails, especially if the download fails, is the expected outcome.

We do not know what happened, but it seems something went wrong and installation was aborted. Aborted in a way that the temp files did not get cleaned up yet. That is also why I asked if you could resume the download. Because of said temp file already being on your disk, this might be possible in some cases.

Worst case (apart from the failing installation/download) for your disk usage situation, the temp file was left in a state where it will not get cleaned up.