I think that this could be another interaction with Juan's calibration Script. Please, could you restart the Javascript runtime? (Script Editor | Execute | Reset javascript runtime). If you don't know how to do this, you could also restart Pixinsight.
I will fix this interaction too but the problem IMHO is in the BatchPreprocess script. After running the calibration script, it is not possible to use the sentence for/in on arrays in other scripts. BatchPreprocess adds a method to the array's prototype so after that every array returns an additional key when used in a for/in.
I will be nice also to have a method for reseting the runtime before or after the execution of an script.