It seems like the letters "c" and "x" are working, but were purged from the site at some point. Any new posts that contain them seem okay, but pre-purge posts are very much not so.
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If I remember correctly, the non-patronus Fawkes also lingered at that cell, which would make sense if there was an innocent trapped in there in place of Sirius.
It seems like the letters "c" and "x" are working, but were purged from the site at some point. Any new posts that contain them seem okay, but pre-purge posts are very much not so.