Everything works up until the final step:
<<<<<<<
Failed to push. If this persists, please file a bug.
Error: Command 'cl land --bypass-hooks' failed: Command '['git', 'cl', 'land', '--bypass-hooks']' returned non-zero exit status 1
>>>>>>>
It said to file a bug. I filed a bug.

https://codereview.chromium.org/2678263003 is the CL it created in this particular instance, but it's happened repeatedly with different CLs.

I tried again and here's what I see when I go to the temporary client and git land -vv:
[D2017-02-07 15:24:07,932 13511 139835722114880 subprocess2.py] git push --porcelain origin HEAD:refs/branch-heads/2987
Counting objects: 7, done.
Delta compression using up to 6 threads.
Compressing objects: 100% (6/6), done.
Writing objects: 100% (7/7), 908 bytes | 0 bytes/s, done.
Total 7 (delta 6), reused 1 (delta 1)
remote: Resolving deltas: 100% (6/6)
remote: Processing changes: refs: 1, done
error: failed to push some refs to 'https://chromium.googlesource.com/chromium/src.git'
[D2017-02-07 15:24:31,133 13511 139835722114880 git_cl.py] To https://chromium.googlesource.com/chromium/src.git
!       HEAD:refs/branch-heads/2987     [remote rejected] (prohibited by Gerrit)
Done