I would suggest , to check the cluster heath from Ganglia, check if cluster is under load . This will give you more info, if this is an interactive cluster we do suggest your jobs to move to job cluster. if your use case required interactive cluster we suggest to do a regular off-on of the cluster and also, check if there is any GC failure happening for the cluster. You may ask MSFT support to open a Databricks colab case and we may look into further. Sorry for the inconvenience caused @Maciej G​