Fatal error: EBADF: bad file descriptor, close

After this error message:
> Fatal error: EBADF: bad file descriptor, close

the current task stops instantly even of there are other things ot do for that task, without other details on issue and grunt quits.
The time elapsed report is printed (so it is not an abrupt exit).

Task prints its progress with progress bar from `progress` with render throttling applied.

The code of task (files upload loop with progress) works fine if called outside grunt by a standard node script with same files list supplied.

node 6.16.0
npm 6.1.0
tried latest grunt and grunt 0.4.0 with grunt-cli.

No repository file or test is identified. Start by reproducing the task's upload loop under the listed Node.js versions, comparing Grunt execution with the standalone Node script and the `progress` bar's throttled rendering. Done means the EBADF failure is explained and the task no longer stops before completing its remaining work.

Written by the indexing model from the issue text.