I have just been bitten by this too.
Is there an expected fix?
Curious how you fixed it IJmert with a uChar as I was using it as below where vFileArray is a uChar array and it is broken with all being only 64k returned?
Get_Field_Value documents.file_Number (RefTable( documents.DocumentData )) to vFileArray
Update
Sorted the int file had the incorrect expected column length which caused the issue