As has been mentioned many times, there is a discrepancy of a few
letters, which from a statistical viewpoint, become negligible in
a text of 78,064 letters.
Ari Haviv wrote:
> If that's the case, then every Torah is posul [invalid] and anyone who says
> a Blessing on the Torah is making a Bracha l'vatalo [blessing in vain]. I
> guess according to this opinion, the Chofetz Chaim made quite a few brachos
There's actually a bit of truth to this. There's a mitzvah d'oraisah
(one of the 613 Torah commandments) to write a Sefer Torah.
Theoretically, this would necessitate a blessing; something along the
lines of "who has sanctified us with His commendments, and commanded
us to write a Torah". Why don't scribes today make such a blessing?
The Chasam Sofer and the Minchas Chinuch both state that since
there's a potential discrepancy in some of the letters, there's a
possibility that we're not really writing a 100% accurate Torah, so
we don't make a blessing.