[Plugin: UTF8 Sanitize] Changing WordPress Date Format Causes Weird Characters

It seems there is some issue with WordPress Date Format.

Each time when one performed a date format change, there is some weird character appears on a site. The old post of a site that runs in WP MU starts to show up weird characters.

Tried all those UTF 8 converters and nothing work. Only the WP-UFT8 Sanitize and choosing the first option works –

Correct the chars when outputting the posts:
Cook the posts output to convert the broken UTF8 characters into their correct values.
This option will not change the contens of your posts.

There is probably some issues with WordPress 3.3 when attempting to change date format.

Wonder if anybody else also face this problem.

http://wordpress.org/extend/plugins/wp-utf8-sanitize/