@darylbowman We had to do a customisation to stop this from happening 

I did find something interesting, while exploring the source code for the ‘Create Purchase Orders’ screen. If the ‘Copy Line Descriptions from Sales Orders’ preference is checked on ‘Purchase Order Preferences’, the SOLine description is included when searching for an existing POLine. Theoretically, this would only consolidate lines also having identical descriptions.

So if the end goal is to prevent duplicating identical inventory IDs because the description is being changed instead of having a different item, this could do the trick.

@darylbowman You’re right, after checking that box it does work! Thanks!