Telegram contact addition problem

You're trying to add a Telegram contact, which only work if this user has a Telegram account.

It's not just like adding a contact to your phone.
You can add this number to your regular contact list, and search it (by the saved name) in Telegram. If the user has a Telegram account - you'll see it.

If you mean that in other phones you can add him as a Telegram contact directly, you might want to try and share the contact from one of the other phones with yourself:

• Open Telegram, find the contact, open its details and select share. Send it to your Telegram account. Don't use the contact attachment button, it works differently.

If that's the case, it's very weird. I really can't see any reason it would happen.