strange zoho.loginuserid being added

strange zoho.loginuserid being added

Hi having been using this app for some time with no problem. Suddenly when my users update the Add_New_Contact form the firstname field gets set to zoho.loginuserid for no real reason? There is no code in my application to do this!! Also it has been working fine and I haven't changed anything - suddenly this has started happening.

Can you help before all my data gets blasted! thanks

App KingsArms Newcomers
I have shared to support email address...
thanks
simon