Funny results in query - Mailing list pgsql-novice

Hi all,
can someone explain why this is happening?

select field1, field2, field3, field4, field5, field6, field7, field8,
field9, field10, field11, field12, field13, field14 from table where
field18 = 't' order by  us_retail_price asc offset 48 limit 6;

returns...
field1
------------+
H1205
B1494
B1496
H1204
B1495
B1497

but ...

select field1, field2, field3, field4, field5, field6, field7, field8,
field9, field10  from table where field18 = 't' order by  us_retail_price
asc offset 48 limit 6;

returns...
field1
------------+
  H1180
  H1179
  H1205
  B1496
  H1204
  B1497

it appears the number of fields i have in the select is affecting the
results.  I don't understand why?

running 7.2.1

Thanks in advance,
Chris