We once had a short discussion about that over on the old mailing list. Sadly, we did not find a quick solution there. However, seeing more people at least confirms that it does not only occur due to a misconfiguration on our side.
Good that you noticed this!
Some explanation and the cure can be found at:
Best wishes, Marc
I can see there are many open instances and looks they are not getting closed automatically.
gremlin> mgmt.getOpenInstances() //all open instances
and if we want to create or disable index we can't do until we close instances and some of the instance could be doing internal works like indexing etc and if we close them we face issues..any way to know what instances are doing?
Please help us