ID Returned From CreateOrUpdate

ID Returned From CreateOrUpdate

Is the following senario in any way possible in the OS Platform:

1) User_A inserts a table row using CreateOrUpdate_Entity with null Id (Autonumber Identity) in Source.
2) User_B next immediately inserts into same table using CreateOrUpdate_Entity Action with null Id
    (Autonumber Identity) in Source.
3) After some other processing, User_A assigns the  CreateOrUpdate_Entity.Id from step 1) to a var,
   but rather than getting the Id for the row inserted in step 1), gets the Id for the row inserted by 
   User_B in step 2)

I don't believe this should happen in any case, but we are experiencing a bug where this is effectively what has happened.  I'm going to setup a test to see if I can make this happen, but I would like to know if anything like this has happened to anyone else.  Thanks.

Are you using SQL Server or Oracle as a database backend ?
SQL Server
Right now I made a test with 5 concurrent processes creating 10000 records each on table A and id reused into table B. Not a single one was out of place (SQL Server, version 7).
If you look at the DB tables, SQL Server is creating those numbers based on a sequence. Unless you have a very serious error with your SQL Server, that should be impossible.

Thanks Guys.  I'll look elsewhere for the cause of the bug.