Root cause is because of discrepancies between ISO time and gregorian time.
Stack trace sample
ValueError: time data '2018-W50-7' does not match format '%Y-W%W-%w'
at _strptime (/base/alloc/tmpfs/dynamic_runtimes/python27g/7e468a4e2dbc991a/python27/python27_dist/lib/python2.7/_strptime.py:332)
at _ConvertISOWeekStringToUTCDatetime (/base/data/home/apps/s~findit-for-me/flake-detection-backend:19725-f99e598.414806298265931470/libs/time_util.py:50)
at ConvertISOWeekToUTCDatetime (/base/data/home/apps/s~findit-for-me/flake-detection-backend:19725-f99e598.414806298265931470/libs/time_util.py:60)
at Report (/base/data/home/apps/s~findit-for-me/flake-detection-backend:19725-f99e598.414806298265931470/services/flake_reporting/component.py:87)
at HandleGet (/base/data/home/apps/s~findit-for-me/flake-detection-backend:19725-f99e598.414806298265931470/handlers/flake/reporting/generate_report.py:16)
at _Handle (/base/data/home/apps/s~findit-for-me/flake-detection-backend:19725-f99e598.414806298265931470/gae_libs/handlers/base_handler.py:224)
Comment 1 by bugdroid1@chromium.org
, Jan 11