Cant create cron jobs via app engine

[stephen84s]

Issue

Was trying to deploy BBQ recently for my project, kept getting the following error while trying to deploy the app to app engine:-

$  gcloud app deploy --project ${BBQ_PROJECT_ID} app.yaml backend-service.yaml config/cron.yaml config/queue.yaml config/index.yaml dispatch.yaml -q
...
....
Deployed service [backend-service] to ...
....
Updating config [cron]...failed.
ERROR: gcloud crashed (TypeError): 'NoneType' object is not subscriptable

Workaround

The app engine deploy succeeds if I skip cron.yaml.
To get around the problem I created all three jobs in cloud scheduler directly. Had to use the HTTP request option with OIDC header and the app engine service account. (For some reason kept getting Precondition check failed when using the App engine option for the cloud scheduler)

Edit:

Probable Cause

Forgot to mention this may be linked to Google recently removing the cron option from App engine and merging it with Cloud Scheduler.