Tab completion is not working for pyspark kernels in EMR studio

When selecting a pyspark kernel for a notebook in EMR studio, tab completion and tooltips (with shift-Tab) are not working as expected. This is especially true for for attribute listing after a dot (.), for example typing in a shell

import os
os.

and pressing tab does not offer any suggestion. Same goes of course for spark session object, both the automatically created one and a manually created one with a SparkSession.builder.appName() call. Things are working fine with a Python3 kernel. I have tried with EMR cluster versions emr-6.6.0 and emr-6.8.0.