Perhaps the timestamp_format option has been changed:

SET OPTION PUBLIC.timestamp_format = 'YYYY-MM-DD';
SELECT CURRENT TIMESTAMP;

current timestamp
'2010-02-20'

That option, plus date_format and time_format, do not affect what is stored, only what is returned as a string across the client-server boundary. Also, the date_order option affects input and output... but again, not what is stored.

Here's how to restore the default:

SET OPTION PUBLIC.timestamp_format = 'YYYY-MM-DD HH:NN:SS.SSS';
SELECT CURRENT TIMESTAMP;

current timestamp
'2010-02-20 08:01:29.953'

If your computer records seconds to more than 3 decimal places, SQL Anywhere will store up to six, and here's how to display all the digits:

SET OPTION PUBLIC.timestamp_format = 'YYYY-MM-DD HH:NN:SS.SSSSSS';
SELECT CURRENT TIMESTAMP;

current timestamp
'2010-02-20 08:22:06.218000'

As you can see, my computer only records 3 decimal places. Here is a test that proves that SQL Anywhere records more; in order to guarantee that DEFAULT TIMESTAMP generates unique values, SQL Anywhere adds 0.000001 to subsequent values that are otherwise identical (the default_timestamp_increment option controls that):

CREATE TABLE t ( 
   pkey TIMESTAMP NOT NULL DEFAULT TIMESTAMP PRIMARY KEY,
   data INTEGER NOT NULL DEFAULT 0 );

INSERT t ( data ) SELECT row_num FROM RowGenerator ORDER BY row_num;
COMMIT;

SET OPTION PUBLIC.timestamp_format = 'YYYY-MM-DD HH:NN:SS.SSSSSS';
SELECT pkey FROM t ORDER BY pkey;

pkey
'2010-02-20 08:22:19.984000'
'2010-02-20 08:22:19.984001'
'2010-02-20 08:22:19.984002'
'2010-02-20 08:22:19.984003'
'2010-02-20 08:22:19.984004'
'2010-02-20 08:22:19.984005'
...