Even though you have enabled Recto/Verso Page in same Cip3 file option, the FlexRip with InkPlanner workflow still produces two separate PPF for each Sheet in the imposition.
Output to separate R and V PPF files is the same whether you enable the Recto/Verso Page in same Cip3 file option in the CIPress Setup or not.
Likely the naming in the ‘Output File Name field of the InkPlanner task writes to a unique file name for Front and Back side of the sheet.
InkPlanner needs to associate the ink data created when you rip the Back to the already created Front PPF. The naming needs to be limited to the Sheet only, to allow the Front to Back association and allow for Back data to be appended to the Front PPF.
In this case, remove the reference to SheetSide in the InkPlanner task's General section for Output File Name and any reference to SheetSide from the CIP3 section for Job Code field.