The question Suggestions on using model in production 1 test at a time was closed as off-topic.
To my mind, the question content is squarely about the generalizability of a specific kind of feature (categorical encodings of particular strings). This seems on-topic! The subject matter seems incidental because OP's question is about a more general kind of dummy variable trap, in the same way that you wouldn't use a categorical encoding of SSN or phone number in a regression model because it uniquely identifies each respondent.
I think that my answer directly addresses the statistical component in its first section. The second section of my answer is probably not on-topic, but since I happen to know about these models, I felt that I could offer some constructive advice. The third section of my answer is about how to construct generalizable features or else use feature-free architectures which support generalizable models.
Would anyone involved in the closure of this question be willing to elaborate on their decision to close?