Fix todo block detection

open-todo-txt.py

@@ -37,10 +37,13 @@ def parse_file(options):
 
             todo_block = get_todo_block_date(line, options.todo_block_title)
             if todo_block == False:
+                curdate = ""
                 continue
             if todo_block != "same":
                 curdate = todo_block
                 continue
+            if not curdate:
+                continue
 
             completed_task = re.search(r"^x ((?:\([A-D]\))? ?.*)$", line)
             if completed_task and options.taskwarrior_log_done: