Hi Niklas,
The numpy array you’re using is deeply nested. This is not supported by our Python integration because KNIME largely works with flat tables (please also see beginner’s posts in your other thread: How to get an numpy array as output?).
I’m not quite sure why the output DataFrame you created is interpreted as a table full of booleans. Trying to transfer the table from Python to Java should actually result in a runtime error. So thanks for reporting that! 
To get your data to Java, you’d need to flatten the numpy array somehow. I’ll gladly help you with that.
Marcel