Hi Christy,
Sorry for the inconvenience caused.This is an already known issue #691"Inconsistency behaviour of the Edit control for Renaming the Node " and it is been fixed internally in the patch 3.3.0.8.
Please upgrade to Essential Suite v3.3.0.8 from the link below.
3.3.0.8 setup
As a workaround you could invoke the TreeViewAdv''s EndEdit method inside the MouseDown event handler .Please take a look at the attached sample,and let me know if this helps you.
Let me know if you need further assistance. We appreciate your interest in Syncfusion products.
Regards,
Deepa.
EditingNode.zip