Even threaded, asking two or more clarification questions in one comment can be frustrating (and a miscommunication bias) for an OP, especially if the OP doesn't speak English as a native language and/or if the OP is feeling "haunted".

Since the community can't really control how many clarification questions are being written in one comment, I suggest to consider these options:

• Printing a small hint like We suggest to ask just one clarification question per thread
• Asking the commenter Is your comment a question? and if the commenter hits "yes" than a the question would be inserted under a What is your clarification question? title with a button labeled Ask another clarification question appearing under the question for a case of need, similar to "add another file" button after uploading an image to a local file tree