Certificates need update
I noticed a movie which in fact had a 16+ certificate in Turkey was recorded as 15+ in IMDb. I was gonna attempt to fix it but then realized you have outdated certificates for Turkey so possibly that's why original contributor couldn't enter the correct value instead chosen a closest value you have.
This makes the database inaccurate. Please update certificates for Turkey. They changed their certificates in 2019 or 2020. You still have outdated options.
You can find the updated info here: https://en.wikipedia.org/wiki/Motion_picture_content_rating_system#Turkey
I know you won't like Wikipedia as source, here are two official URLs from "Ministry of Culture and Tourism" to confirm info on Wikipedia is correct:
Please fix this soon, I mean don't forward it to the "appropriate team" and then forget about it for 10 years. Thanks.