Object in collection does not appear on collection view - but I can't recreate this behaviour

I'm going to record this because it's weird, though I haven't been able to recreate it.

1. A test authenticated user with permissions to add and view Islandora objects adds a large image to the large image collection provided by default in the 7.9 release VM.

2. The object is manipulated (datastreams deleted and regenerated, edited) and then the user navigates back to the main collection view. The object is not visible.

3. Viewing the manage tab, the object still exists and is linked to the default large image collection.

There is no policy datastream on the object.

I sought to recreate this behaviour with another object, navigating back to the collection level after each action I had taken previously.

On ingest: Image still appears in main collection view
Delete TN: Reverts to folder view
Delete JP2 & JPG datastream, no change
regenerate TECHMD, no change
replace OBJ, no change
delete version of MODS, no change
revert version of MODS, no change

Just in case somebody else sees this behaviour in the release VM...