There have been some changes around data types recently and it appears that the data type in a DCI is now both, the expected data type for in- and output.
For some transformation scripts that may not be desirable though. For example data might come in as a string, but the transformation script returns an integer. This integer will now be treated as a string and thus line graphs don't work (just showing "0").

Not sure if it would be possible to allow users to optionally have different in- and output data types?

Cheers