We have production process for backflush items. When you complete production is there anyway to reverse the original entries for completion with a link to original production order. Currently only option I can find is doing a disassemble production order. However 2 issues with this, first there's no link and automatic reversal for original entries. Second I cannot reverse the labour and other resources through this way. If we had a data entry mistake how can we easily reverse it like purchase receipt to purchase return or cancel the document?
Currently there is no such functionality in B1. As you suspect, you will have to separately do a disassembly for faulty production orders.
Assuming this does not happen too often, you can just take the faulty production order, duplicate it, and change the duplicate to "Disassembly". However, you would still have to do the Receipt from / Issue for Production.
If you (or a colleague) have any coding skills, you could build a small application that would do all the work with the click of a single button, or you could ask your SAP partner to build such an addon for you.