Kenneth writes:  I am searching Civil Registration (Tribunale) for birth records of my grandfather and his siblings (on the FamilySearch website). In the process, I’ve uncovered an unusual situation, and hope an Italian genealogy expert can explain.
There are 5 siblings born in 1881,Caterina 1890,Virginia, 1891,Maddalena 1894 (or 92)Vittoria and 1896 (Battista-direct ancestor)
My grandfather Battista Pedroncelli (b. 1896) is in the Comune di Verceia film, along with Virginia Maddelana (b. 1891) and Vittoria (b.1894).
Catterina (b. 1881) is in the Comune di Madesimo (Isolata) film.

Giovanni Maria (b. 1890) in both the Verceia and Medesimo films.
An acquaintance searched the Madesimo church records, and found a different birth year for Vittoria (as b.1892). There are no other Vittorias in the the 1892 Civil Records to cause an error or confusion. I don’t have a copy of the church records (just notes). The gap is strange because the church record indicates a 1892 baptism and the civil registration is May 1894. Is it possible the civil record wasn’t entered for almost 2 years? Any idea why such a big difference in years?

Without seeing the actual records it is difficult to give an opinion. However you need to bear in mind that church records reflect BAPTISM dates, not birth dates. They are usually close but not always. Sometimes a child will be baptized at the moment of birth if they are in danger of dying before the priest gets there. If the child dies immediately the priest will record the baptism but the town may register a ‘born dead’ which you won’t find in the birth registers. Usually in the ‘diversi’ (different or miscellaneous).   The town cannot register a death if a birth wasn’t registered. I am pretty sure it is a different child. It is very common to reuse a name from a child that died.  If the first Vittoria died in then the next female child would receive her name, especially if it was a Grandmother’s name.

I found Giovanni Maria (b. 1890) in both the Verceia and Medesimo films. Is duplicate registration common? Even with my limited Italian, I’m 99.44% sure the Giovanni I found in both towns is the same child. Birth dates and parents are identical. Although there are A LOT of Pedroncellis in Sondrio at this time, I think his father is the only adult Giovanni married to Maria Pilatti (and, it fits the family’s 2 city story).
This may provide more context:
The Verceia entry is recorded in Parte I (the official “printed” form).
The Madesimo entry is recorded in Parte II (all handwritten). It follows the format of the official form. There are also statements not usually found in the printed forms (which I can’t translate w/ my limited Italian).

The one from Parte 1 Verceia is the original birth registration in the town where the birth took place.

The one in Parte 11 Madesimo is the courtesy copy sent by one town (Verceia) to theofficial  town of residence (Madesimo)of the family. 

Parte 1 is where they put all the births that took place in the town itself.  Parte 11 is where they put the out of town births, even from America if the consulate forwards it as Italians can register themselves as ‘living outside the country’.