The poll functionality for anonymous users randomly freezes

At random intervals the poll functionality prevents anonymous users to vote. It could be related to user agent string that's used to generate hash for each vote.

First aid help is to check results from SQL query:
SELECT * FROM poll_vote WHERE uid = 0 AND hostname NOT LIKE '%#%'

If results are found, execute query:
UPDATE poll_vote SET hostname = CONCAT(hostname, '#', RAND()) WHERE uid = 0 AND hostname NOT LIKE '%#%'