Comment 2 for bug 1620139

Pádraig Brady (p-draigbrady) wrote :

Yes that operation was changed in 8.25 to ensure atomic output,
thus allowing one to run multiple factor processes in parallel
and collate the output.

I'll look at disabling this internal buffering if the output is line buffered
(which it will be if outputting to a terminal, or if stdbuf -oL is used)