BUG #13964: unexpected result from to_tsvector

The following bug has been logged on the website:

Bug reference: 13964
Logged by: Ruxandra
Email address: ruxandra(dot)durus(at)vauban(dot)ro
PostgreSQL version: 9.5.1
Operating system: Cent OS 6.7
Description:

Hello,

My version of PostgreSQL is:
"PostgreSQL 9.5beta1 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 4.4.7
20120313 (Red Hat 4.4.7-16), 64-bit"

More details about the operating system:
Linux javatesting 2.6.32-573.7.1.el6.x86_64 #1 SMP Tue Sep 22 22:00:00 UTC
2015 x86_64 x86_64 x86_64 GNU/Linux

I am using pgAdmin version 1.20.0 to query the database.

I am using your full text search (which works great), but i have a small
problem:
SELECT to_tsvector('simple', 'test(at)vauban-reg(dot)ro');

returns "'test(at)vauban-reg(dot)ro':1"

which is exactly what I need.

But when I run :

SELECT to_tsvector('simple', 'test(at)123-reg(dot)ro');

I get:
"'123':2 'reg.ro':3 'test':1"

instead of "'test(at)123-reg(dot)ro':1"

>From the documentation here
http://www.postgresql.org/docs/current/static/pgtrgm.html , point F.30.4. I
understood that with "simple" option only space is a separator for the
stems. Is it a bug or am I doing something wrong?

Thank you for your time,
Ruxandra Durus