Now I say this without any prior knowledge of RoT or having never played anything related to RoT ever
Consider the following sequence, initially kerisreturn is 0
1) You kill SASORC01 (setting kerisreturn to 1)
2) Go to whichever DINAN2 is in (sets kerisreturn to 2 and spawns DINAN3 while destroying DINAN2)
3) Go to area DD9000 (sets kerisreturn back to 1)
4) Go to where DINAN3 is and DINAN2 used to be (sets kerisreturn to 2 and spawns another DINAN3, destroying a DINAN2 which doesn't exist

)
5) Repeat for CLONE ATTACK!!!
... see?? There's a cloning possibility there

Also, wouldn't the !Exists("dinan3") trigger for CreateCreature("dinan3",[708.639],4) prevent respawning even if the actual reason was something else??