Isn't VisualEditor supposed to be able to edit only the content of the table cells but not change the table structure? If so, I believe this should not happen:
https://pt.wikipedia.org/w/index.php?diff=38365876&uselang=en
Version: unspecified
Severity: normal
Any specific steps that resulted in a broken table? And the table was edited only in VE?
I'm not sure how the anonymous user managed to do that.
Since the edit was marked with "Tag: VisualEditor", I assume the user didn't change to the wikitext editor after he started his changes (in that case it would be marked as "VisualEditor: Switched", I think).
I'm setting this task's status to stalled as long as clear steps to reproduce are not known (plus this issue is now a year old).
Table editing has changed dramatically since this bug was filed (for example, the visual editor can now change the table structure), so I'm closing. Reopen if you can still reproduce.