I have looked at the code and also tested it and cannot repliacte the behaviour and the the plugin’s codedoes not behave that way (at least for non logged in users).
Some questions for you
- Were you logged in when this occurred, the plugin could behave that way if you were, I am not sure on this and it is harder to test
- If not have you deactivated all other plugins? I ask as they are a potential cause of conflicts and many are poorly coded
- I was logged in when I noticed this issue, I also enabled commenting for only logged in users
2. Yes I deactivated other plugins