It tries downloading the files, and throws the ClosedChannelException (which is fine), but after a few attempts it just skips the file as 'x'. The partial download is present in the download folder. This didn't happen earlier.
Unfortunately, that stuff is happening within the telegram library I'm using. Just ignore that error - when you run telegram_backup the next time, it will find the partial downloads and continue them.
Here's a picture of what happens:
It tries downloading the files, and throws the ClosedChannelException (which is fine), but after a few attempts it just skips the file as 'x'. The partial download is present in the download folder. This didn't happen earlier.