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What does it mean when there's an Error (1) Under "TRACKERS" ?
Does that mean there's an issue with the file, or it just means that there's an issue with the tracker information and It's relatively insignificant?

The file did download to 100%.

It could just mean the tracker is offline, dead or not reachable at the current time.
Unless the torrent is private, you don't need any tracker(s) to download (as long as DHT is enabled).