This problem was related to https://issues.apache.org/jira/browse/HIVE-9223 but it's not the entire story.
Hue 4.2.0 was working when user configure `max_number_of_sessions > 1` , and on the HUE notebook can run concurrent query in different tabs up to the set sessions of `max_number_of_sessions`, one query per session.
However, after HUE 4.3.0 this function has been failing and didn't respect the `max_number_of_sessions` set in hue.ini. the root cause was HUE-3287 introduced a bug when using incorrectly ENUM for checking if a session is busy as submitted or running.
With this fix and tested on HUE 4.5.0, we have the concurrent query per session function back, and potential close the HIVE JIRAs HIVE-9223