On leveling my cleric his Holy Symbol (and prayerbook) were taken from his inventory and replaced by a "new" starting level Holy Symbol (with only +2 Appraise, rather than the +1AC, + Reflex + Spellslot, + Persuade etc.).
I am presuming (hoping) that this is not intended to happen.
How long did you have the past symbol for and how many converts?
Had the past symbol for a month or so at least. One convert.
No bug. You'll see it updates more frequently now. Talk to me on IRC about the convert.