interp: different behavior of `pipefail` for multiline scripts

[Hades32]

I'm using Task and hit this issue and was directed here: go-task/task#392 (comment)

I want my script to fail on pipe errors. cmd1 works/fails as expected, but cmd2 never fails:

  cmd1:
    cmds: 
    - set -o pipefail ; aws something | jq .someField
    - echo success # this never happens if aws fails

  cmd2:
    cmds: 
    - |
      set -e
      set -o pipefail
      aws something | jq .someField
      echo success # happens despite error in the aws command

Why does pipefail not work in the second case?