Specifically, when the fictional language is used in places outside of the works they appear in:
What does this elvish text from UC Irvine say? is okay
Grammar and quality check for a Klingon warning notice for server room is a current question, has 3 close votes at the moment
Is this Gallifreyan, and what does it say? is a surprising request because there's so little to go on, but it had an answer
What is written on my Mjolnir? is about a licensed product with runic gibberish
There may be more, I only looked through the first couple pages of a search for "translate", and they may have appeared in other ways.
It may not be enough to be too concerned about, but with one such question locked by a CM (I think the context was not good on that one, but that could be edited out), and a current one getting a close vote, I'm wondering about how to vote.