gs://chromium-layout-test-archives/linux_precise_blink_rel/3863/ contains 4 entries:

  failing_results.json     14/10/2016, 09:48
  full_results.json	   14/10/2016, 09:48
  layout-test-results.zip  14/10/2016, 09:45
  layout-test-results/

gs://chromium-layout-test-archives/linux_precise_blink_rel/3864/ contains many entries:

  access_log.txt           14/10/2016, 09:44
  accessibility/
  animations/
  ...
  failing_results.json     14/10/2016, 09:47
  full_results.json        14/10/2016, 09:47
  ...
  layout-test-results.zip  14/10/2016, 09:44
  layout-test-results/     (empty)
  ...

All of those extra directories and files are supposed to be under layout-test-results.
Given that I recently made some changes in archive_layout_test_results.py, it seems
likely that one of my recent changes is responsible.