Question
Can I remove Objects in Container “cn=temporary”?
Answer
Yes, if they do not disappear you can safely remove them.
Investigation
These objects are created to ensure that no duplicates are created. They are usually marked with a lifetime entry so they will get removed after a while.
The objects are not always deleted automatically. Verfiy the corresponding object exists in OpenLDAP (or it is a deleted object). Then you can safely delete these entries from cn=temporary.