Spelling and Grammar doesn't underline typos

I’m reading *** BUG REPORTING: Please read before posting! ***. Should I re-post this under bug?

Anyway, detailed reproduction steps:

  1. Create a new Scrivener project. I used the “General Non-Fiction” one.
  2. Open the Scrivener project. Ensure that under the Edit > Spelling and Grammar menu the Check Spelling While Typing option is enabled. In my test, I’ve left the other options disabled.
  3. Go to any empty document. I used the pre-created one under Manuscript > Chapter > Section.
  4. Type these exact words: How iss this even posible, preccious?
  5. Expectation: the words “iss”, “posible” and “preccious” will be underlined in red as typos.
  6. What actually happens: “preccious” is underlined in red, but the rest of the sentence is not.
  7. Repeat this in a new TextEdit document: the typos will be highlighted as expected.