I agree that calling Tichynob by what is essentially a nick name is weird. I am a Robyne. I do not like being called Rob although family members and others who have known me for over 30 years can do so without retribution. It is a very familiar nick name.
I have a Rob like character in my past and when I refer to him I call him by first and last name with his middle initial explained as “P for prick”. Interestingly, he is also a Robert generally known as Rob.