When I said 'not validating as it should' this is what i meant: When I enter a number in the name field no error comes up. When I enter a name in the number field no error comes up.
When you enter a number in the name field, there is no reason it should not validate. A number is a 'legal (text) character'. A lot of textfields 'uses numbers', like 'Taxi-1' and 'Someroad 23'
Your number field has been defined as a textfield and is behaving as it should.
If you need to validate numbers (by using 'math'), you need to define it as Int (usually)
So, if you phone can only be 4 digits, it would be something like this