TS Printing through Thin Client - random duplicate print jobs

I have a customer using Neoware Capio thin clients with autocreated printers
on a Windows 2003 Standard Server. The printer attached to each Neoware is
an OKIDATA ML320 dot matrix using the Microsoft Generic Text Only driver.
For the most part they print just fine. At times though, when 2 users go to
print at approximately the same time, their print jobs not only print on
their local attached printer it also prints on the other individual's printer
as well. They get two copies of each print job, one on each printer.
I have worked with Neoware support and they are now throwing up their hands
and pointing to MS. I could sure use some assistance.