I have an anecdote that I think fits your assumption. It comes from my years in the Danish public sector where some of the systems are many decades old. In Denmark we’re all issued a social security number that is designed in such a way that the last number of it, is odd for males and even for females.
To make things short and somewhat anonymous, we had several systems that couldn’t handle people changing the “gender” of their social security number. They could handle you getting a new social security number, but it had to be of the same “gender” as your previous.
This makes no real sense, as it’s just a number and all these systems handle both types of numbers. But there we were, and it took us several years to get to a point where we could accommodate an employee changing the “gender” of their social security number.
So sometimes, developers do weird things because of their assumptions.
Ps. I’ve put “gender” in “”s because I’m unsure what the right word is in English.