[Info-ingres] Same select statement doesn't consistently return same number of rows

[Dennis]

Ingres
II 9.2.4 (a64.lnx/100)NPTL
14674
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II 9.2.4 (a64.lnx/100)NPTL

select * from table where col = 'xxxx' will return different number of 
rows on different runs of the sql.  I know that no one is 
updating/inserting rows that affect col = 'xxx'.

If I run select count(*) from table where col = 'xxxx' then the row 
count is consistent across different runs of this sql.

On another system that only differs in Ingres version (9.2.1) I don't 
have this issue.

Both systems have
cursor_default_open READONLY
system_isolation READ_COMMITED

What should I be looking for to resolve this?

Thanks

Dennis