On short prompts, commands wider than the terminal do not reposition to start on their own lines.

screen.cpp

@@ -1215,7 +1215,14 @@ static screen_layout_t compute_layout(screen_t *s,
         result.left_prompt_space = left_prompt_width;
         // See remark about for why we can't use the right prompt here
         //result.right_prompt = right_prompt;
+
+        // If the command wraps, and the prompt is not short, place the command on its own line.
+        // A short prompt is 33% or less of the terminal's width.
+        const size_t prompt_percent_width = (100 * left_prompt_width) / screen_width;
+        if (left_prompt_width + first_command_line_width + 1 > screen_width && prompt_percent_width > 33) {
             result.prompts_get_own_line = true;
+        }
+
         done = true;
     }