I'm experiencing the same problem. At one node in particular in my script my walker stops working. I don't think its a map click issue because:
1) Manually map clicking works.
2) Manually walking to the node and then back to update creature locations stored in Tibia memory does not get the walker working.
3) Switching back to arrow key mode does not get the walker working again. In fact nothing does besides closing and restarting the client.
4) After getting stuck, it doesn't matter what node or label I'm on, the walker refuses to do anything. Not even label code or one-liners are executed.
Furthermore, Walker.Delay(0) and all the other lua commands to start and stop the walker and whatever don't do anything. It's probably not an infinite loop or delay in my script as my modules continue to work normally, and killing all my running scripts does not fix the problem.
Here is a video recorded after the issue occurs. I killed the scripts and changed the pathfinder before recording. This happened about 2 hours into a botting session.
@DarkstaR