Hmmm... Not sure how to trace that with GDB.
I'm not sure how to handle child processes.

The offending libpipeline call is "pipeline_pump" in src/man.c:2329 in the
"display" function.

I'd need more time to investigate this, time which I don't have at the moment,
sorry :(

-- 
Pierre Neidhardt
https://ambrevar.xyz/