vision radius problems

Hi Alex and everyone!

I've started using Quelea a week ago and I have an issue with vision radius. As you can see at the attached file, using the contain force component,  I want the agents to avoid the environment's boundary at the time they "see it". That means agents should steer away when they approach boundary at 1 meter distance, (1 meter is also the vision radius and the agents body radius). I set everything but when I run the timer it seems that agents have a random behaviour approaching the boundary. I have the same problem using separation, cohese etc. Any ideas why is this happening? I need the vision radius to represent actual distance at any case

Thanx in advance!