Very often, spoilers are not blurred, although they are correctly formatted with the “spoiler” tags. Can be quite frustrating at times.
Here’s an example from the show “Russian Doll”. The first review is blurred because it contains spoilers. The second review is not blurred even where it is marked as “spoiler”.
This seems to be a problem with moviebase, not with trakt. Here is the same review on trakt.com: https://trakt.tv/comments/217681