As the video demonstrates, the pathfinding algorithm takes off-screen creatures into account. This means that you can get stuck even after those creatures have moved away from their blocking positions. At 0:28 I unstick my character by pausing the bot and manually walking until I get the critical position on my screen. Ignoring off-screen creatures would solve this bug. However, you might also want to consider ignoring only creatures that have been offscreen for X amount of time.
Note: I'm walking with arrow keys.