Commenting on a diff failing

https://sentry.gitlab.net/gitlab/gitlabcom/issues/3190511/?referrer=gitlab_plugin

DiffNote::NoteDiffFileCreationError: Failed to find diff line for: lib/gitlab/json_cache.rb, old_line: , new_line: 28
  app/models/diff_note.rb:46:in `create_diff_file'
    raise NoteDiffFileCreationError, DIFF_LINE_NOT_FOUND_MESSAGE % {
  config/initializers/forbid_sidekiq_in_transactions.rb:58:in `block in committed!'
    Sidekiq::Worker.skipping_transaction_check { super }
  config/initializers/forbid_sidekiq_in_transactions.rb:10:in `skipping_transaction_check'
    yield
  config/initializers/forbid_sidekiq_in_transactions.rb:58:in `committed!'
    Sidekiq::Worker.skipping_transaction_check { super }
  lib/gitlab/database/load_balancing/connection_proxy.rb:126:in `block in write_using_load_balancer'
    connection.send(...)
...
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