How often do teams actually get to build POCs that aren’t expected to go into production in some form?

I just ran into this again. I asked explicitly if the code I was writing was going to be throwaway, was told yes, but then when we wanted to move it to dev, I was told we needed test coverage... And of course, now we have a half-baked but working solution in production. Sure, we can refactor it, but it's so much more of a pain now since we have to worry about migrating real data without interrupting anything, when we could've just quickly built a better version with what we learned from the POC.

Is this just the reality of software development, or am I just unlucky?