To reproduce:

• Create a CSV file with [[links]] in double square brackets in the content. (Use the attached example file.)
• Edit a page in VE.
• Drag the file to the page being edited.

Observe:

• While editing, you'll see [[ASCII]].
• After saving, you'll see <nowiki>[[ASCII]]</nowiki>.

The saved wiki syntax corresponds correctly to what is shown in the rendered table, but it's not necessarily what the user wants. It may be hard to guess whether the user actually meant to write wiki syntax in the CSV, and whether it should be put into <nowiki> or rendered as wiki syntax. Evidently, VE can identify wiki syntax; for example, it does it with pasted content. So perhaps it could be done also with CSV content.

Needless to say, the functionality of converting a dragged CSV to mostly-usable wiki syntax is generally brilliant! I didn't even know about it until a wiki editor mentioned that he used to create wiki tables, but he did hope that his wiki syntax would be rendered as such and not surrounded with <nowiki>.