Email Activation Error #7346

When i click on the email confirmation link send when registering a user, sometimes it thorws a error and sometimes it passes. Can i please know why this is hapenning? The error occures when user clicks the activation link from mobile. After retrying sometimes then it passes.

Please see the audit logs,

If i click the link from the computer web application it pasees.

below is the error received,

Can anyone help on understanding why this issue happens?