Why does GG extract "Lag at Chkpt" indicate a different time zone from database and server sessions?

We have a 2-node RAC database on Solaris LDOMs.

The servers themselves run in localtime (TZ=localtime). In this case localtime means CT.
The database time zone has been set to UTC: ALTER DATABASE SET TIME_ZONE='UTC'

The database and listener are running in UTC:

srvctl setenv listener -l listener -t 'TZ=UTC'

srvctl setenv database -d DBNAME -t 'TZ=UTC'

And at the command line for the database and the grid, the time zone is UTC:

$ echo $TZ

UTC

The config files for the grid remain set to localtime.

In $GRID_HOME/crs/install/crsconfig_params and $GRID_HOME/crs/install/s_crsconfig_SERVERNAME_env.txt we have: