A change in HTCondor 8.2.9 makes the setpgid call in pegasus-dagman fail with:
os.setpgid(0, 0)
OSError: [Errno 1] Operation not permitted
The change in HTCondor:
https://htcondor-wiki.cs.wisc.edu/index.cgi/tktview?tn=5173
It seems like HTCondor now sets the process group already to match the pid, and hence the setpgid fails.