Why would the "Suppress Invalid data" selection not be enforced on a data form?

Summary:

Invalid data is still appearing on the data form, despite having enabled "Suppress invalid data - rows".

Content (required):

We created a data form with valid intersections applied to the members used, and ticked the "Suppress invalid data - rows" selection.

When running the form, the invalid cells are still on display - although they are greyed out and not inputtable.

We have another almost identical form, where this is not an issue. The same valid intersections are applied, with the "Suppress invalid data - rows" ticked.

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):