> I think it's because the complexity of the tasks varies, and it's also difficult to predict this complexity.
I don't know what that means in relation to the Kanban methodology.
What I'm looking for is something like, "my manager attempted to improve our cycle time by introducing limits on the number of tasks that can be in each state on our board. When a limit is exceeded, we are expected to take a predefined action to help clear the bottleneck that caused the pile up. It doesn't work and we still have bottlenecks and have not improved cycle time or efficiency."
If all your manager is doing is putting arbitrarily limits on WIP columns, that's unlikely to accomplish much and thats not Kanban. This kind of limit is only beneficial for the person who starts too many tasks without finishing them. The Kanban methodology is about team efficiency, not individual task limits.