Hi Deep,
Movement type ZZ1 is a custom movement type. please provide more details like from which standard movement type this movement type was created. this will explain why the RG1 register is getting hit. usually when we create a new custom movement type ,then we also create the movement type reversal. for example if i have created a new movement type ZZ1 by copying the standard movement type 101, then i will also created ZZ2 movement type by copying the movement type 102.
Please check for the reversal of the custom movement type ZZ1 and reverse the document.
Regards