How to debug error "Signal SIGCHLD received, but no signal handler set."?

[com]

Hi there,

I use Cygwin (updated to latest packages) with the latest parallel version
(20160622).
My workflow looks like this:

     cat input.txt | parallel --pipe -N64 --blocksize 63K  --joblog
joblog.txt --retries 3 --progress  python myscript.py

myscript.py does some CPU-bound processing with some network I/O and takes
about 3 seconds per input line. input.txt has about 360k lines.

The above command works well for about 30-60 minutes, fully utilizing 16
cores. But then, it stops with

     "Signal SIGCHLD received, but no signal handler set."

on STDERR. I tried to simulate the command with

      seq 360000 | parallel --pipe -N64 --blocksize 63K  --joblog
joblog.txt --retries 3 --progress sleep 3

But I could not replicate the error yet.

Does anyone have an idea how to debug/resolve this?

Thanks
Stephan