We have recently noticed that feature layers views do not function correctly in an AGOL Open Data Portal.
We have a feature layer view which represent the data from a feature layer that we wish to expose to the public as open data. This workflow is extremely useful and efficient as it means we do not need to duplicate data.
However when you click on the feature layer view in the open data portal the entire dataset without the definition query of the view is displayed to the user. This is quite a dangerous bug.
Our open data portal is not public yet so I can't share a link.