Isn’t this clear evidence that the registrations were invalid in the first place?
Not quite.
As others stated, people un-registering could have been due to various reasons if the number had been in the dozens or a couple hundreds.
But the number of 3400 is significantly higher than ‘normally expected’.
And here we are, we are guessing right now.
[Note: my last paragraph is sarcasm, in case it didn’t come across as such.]