I just saw this not with multiple items, but when I choose an attachment, then expand selection to include the parent item by keyboard action (with shift pressed), and finally right-click on the attachment to delete the selected item+attachment. It asks if I want to "move the items to the Trash?" but after confirming, it collapses the attachment, not delete the item.

I tried other combinations of clicking and selecting; deleting works fine. Unfortunately, this is how I seem to select and delete. Debug ID: D661348844

Absolutely. Disabled all plugins, except the stock word processor plugins.

Download random academic PDF into Downloads folder. Drag and drop into empty collection named "Temp". Zotero fetches proper metadata and created parent item with renamed PDF attached. Click on the attachment to select it. While pushing shift key, hit up arrow key to select the attachment+parent item. Then right-click (i.e. two-finger click on MacBook Pro trackpad) on attached PDF, and choose Move Item to Trash in the context menu that appears. Click on OK. The result is a collapsed item, but nothing has been moved to Trash.

Here is a Debug ID that starts with item creation: D2124779362.

@enozkan: Fixed now in beta 42.