Since upgrading to 803ESP6 user have been seeing strange things when entering PO's. Some users are seeing lines disappear after adding a line to a po. They fill in the function as A for add then enter the line the press Change. After doing this, the line disappears and never comes back. Just like it was never entered.
Has anyone else seen this happen?

803MSP9
803ESP6
AIX 5.2
Oracle 9i

We've recently upgraded to the same Apps/Env level that you have, however running Windows w/SQL Server. After upgrading, one problem we had was entering [I think it was] invoices. The A/P Coordinator came over and told me that entry worked differently. It was necessary to add lines, then go back and edit them afterward. They couldn't be changed 'on the fly' like before.

Lawson CSG confirmed that this was how it was supposed to work now, and they won't go back to how it used to work.

What I'm talking about is not to attempt to solve your problem, but to point out that the functionality of the program may have changed! Check your users' expectations -- they may be doing things "the way we've always done it" and now that may not work.... Good luck.