Parameters won't show in the URL if the URL string is too long. They'll just exist in the pages POST data. Enable Joomla debug mode and review the query at the bottom of the page in query debug information. It should start with the following.
Code:
SELECT ue.*, u.*, '' AS 'NA'
FROM `jos_users` u
INNER JOIN `jos_comprofiler` AS ue
ON ue.`id` = u.`id`
WHERE u.`block` = 0
AND ue.`approved` = 1
AND ue.`confirmed` = 1
AND ue.`banned` = 0
Note your table prefix may not be jos_. You'll see any search parameters added to the WHERE statement of the query.
Have retested age range searching and appears to be working fine in my tests. That behavior hasn't been touched in a very long time so there's no reason to suspect it doesn't suddenly work now.