Yup. The full name of the converts is xxx ben Avraham
avinu (xxx son of Abraham
our father) or xxx bat Sarah Avraham
avinu (xxx daughter of Abraham
The "xxx" is very often Abraham
Female converts will also have another name: xxx bat Sarah
imenu (xxx daughter of Sarah
It's not surprising. Jewish women have two names: xxx bat [name of the father] and xxx bat [name of the mother].
A man who would be called xxx ben [name of the mother] would be the son of a Jewish man who converted to another religion or a bastard. It also happened a couple of times in North Africa
, when the parents were divorced and the son clearly sided with the mother.
I hope it helped!