BUG #8067: now() bug?

The following bug has been logged on the website:

Bug reference:      8067
Logged by:          Istvan Kassai
Email address:      kako@zhnet.hu
PostgreSQL version: 9.0.1
Operating system:   Linux DRONE 2.6.32.27 #5 Wed Dec 21 12:11:46 CET 2
Description:        =


function "now()" sometimes returns with a value with timezone data,
sometimes without.

for example:

*****************************************
therm=3D# select now();
            now
----------------------------
 2013-04-14 06:58:12.056065
(1 row)

therm=3D# select now();
              now
-------------------------------
 2013-04-14 08:58:12.766165+02
(1 row)

therm=3D# select now();
            now
----------------------------
 2013-04-14 06:58:16.046629
(1 row)
*****************************************

is it a bug or a feature?