Canceling Write-In Votes Changes Other Votes

I have set up a binary poll with a few choices, and the ability to submit write-in votes. Users have permission to cancel their own vote, and can then resubmit a new vote. Maximum choices is set to 1.
I'm still trying to narrow down exactly what is happening, but I'm not much help when it comes to deciphering the code. Here's the scenario I'm running into:

User A submits a write-in vote for "X"
User B submits a write-in vote for "X" (same write-in as User A)
User A cancels their vote, then resubmits a new write-in vote for "Y"
User B now shows votes for both "X" and "Y", and both are counted in the results

User B ends up with two votes cast, one of which is for something they didn't even choose. This is obviously a showstopper for any serious poll that needs this configuration.
I'm not sure what the root of the problem is, though I wonder if it might be related to this issue: http://drupal.org/node/274533

The only workaround I've been able to think of at this point is to disable the permission for users to cancel their own vote. This is a minor annoyance in most cases, but I'm still left with an uneasy feeling after seeing this bug cause a blatant miscount.

I really hope this module can make it past the issues that have been showing up. The core Poll module is far too limited, but it seems the maintainer of this module has been AWOL for some time...