Navigate to Lexeme:L100000, click "discussion" tab, and try to create the page. I get Permission error (both as a logged in user and as anonymous)
Permission error You do not have permission to create this discussion page, for the following reason: You are trying to create a talk page which cannot be associated with a lexeme. Therefore saving this edit was blocked. You should check whether the title of the talk page is typed correctly. If you think you are correct, please contact an administrator.