Hi, thanks for playing the game and leaving your comment!
The left mouse button should not count as enter, and I cannot reproduce this issue on my end. Are you sure you're not clicking the submit button by accident, or something like that?
It would also be great if you could say what browser you're using and are you on desktop or mobile. Does it happen every time, or only sometimes (and if sometimes, when does it happen), and does refreshing solve the issue? A video showcasing the problem would also be nice, but I understand if that might be difficult. This information would be really helpful in pinpointing the issue.