Duplicate Lead Created Upon Save

Duplicate Lead Created Upon Save

I am new to Zoho and I am simply entering leads one by one.  After I enter the fields and click SAVE on the top right I see a column that says "All Open Leads"  and there is a duplicate for the lead I just created!  I can click the down arrow and delete the second lead but can you tell me why is the duplicate being created?

Thank you!

SBP