Touching production stuff without prior contact with it seems risky. I was "forced" to do so a couple of times but always considered companies putting anyone ill-equipped on prod as... doing maybe too much savings at the cost of service quality.

I left every single company which wanted me to spend a lot of time (weeks, months) to figure out their custom stuff due to no documentation and lack of people who worked on this and knew what makes the thing tick or what to do when it stops. Having noone or a single person kind-of knowing how to do something in a company is a managerial knee shot.

I value my learning/working time maybe more than an average person due to focusing issues. Spending it on figuring something which could have been documented but wasn't absolutely isn't my favorite thing to do. Weeks of detective work are weeks when I'm deprived of ability to learn something useful for my next job.

So while this GitLab post doesn't specify what kind of things are there to figure out, I consider stating that there's always something to figure out as unprofessional as it points out possibly unprepared staff.