Difference in output when storing iterative using flag -i and storing non-iterative on masked input data

There is an difference in the output using iterative-storage and non-iterative storage, i.e., with or without the flag -i, on masked input data.

E.g., climix -e -v -i -o /path/to/output/file.nc /home/rossby/joint_exp/climix/1/testdata/NGCD/annual/Aland/NGCD_RR*.nc -x r10mm

In the output the masked area is filled with value 0. Whereas, for

climix -e -v -o /path/to/output/file.nc /home/rossby/joint_exp/climix/1/testdata/NGCD/annual/Aland/NGCD_RR*.nc -x r10mm

the masked area is still masked, i.e, filled with 1e+20.

Loading the output cubes and looking at the data, there seems to be a difference where one has a defined mask with shape (49, 75, 56) and the other one has the default mask=False with shape ().