Why an OTP sent to my phone whenever I login a new device? Is it a default?

It is a default whenever you login a new device to ensure the safety for your account.

If you recognize any strange actions on your account, even you haven’t logged in to your account but there are OTP(s) sent to your email, you can immediately call Timo Care on 1800 6788 to inform us of the problem to get further assistance.