I am having problems copying a CDT array into an CDT array that is in a CDT. It

Are you mapping individual fields from source to target CDT using script task!

No. I'm copying an entire CDT array to a CDT array that is inside another CDT pv that is not an array.

Actually, inside a script task, I use an activity class variable of a CDT type in the custom input tab. I fill values individually to that activity class variable, then in the output tab I append that activity class variable to the CDT array pv. That works fine.

But, if I append that activity class CDT variable to a CDT which has the exact same array CDT type field, the copy succeeds, but only the integer values are copied but not the text types of fields. Strange.

Can you please attach the cdts structure and mapping screenshot.

"CDT array that is inside another CDT pv that is not an array" ->Are you trying to say that target CDT is nested type (see the attachment) and you want to copy location data (another CDT with similar structure) to company CDT type .

Any specific reason why you are using "activity class variable" of script task for it. You should use 'outputs' tab of script task for data mapping.