timing reported by `cado-nfs.py` are sometimes inconsistent / incomplete
Some of the problem description here: https://lists.gforge.inria.fr/pipermail/cado-nfs-discuss/2020-September/001302.html
Some of the problem description here: https://lists.gforge.inria.fr/pipermail/cado-nfs-discuss/2020-September/001302.html