I hated those sorts of GUI bugs.
The problem is that when you set up the initial display caption, it triggers the function that checks for clicks on the button...
Graphs work fine for me in 2.4.9, and I didn't change anything to get to 2.4 from 2.37 in this regard I don't think... Anyway, are you sure that no mutations are happening? remember that if all bots but one have 0 mutations, and one bot has like 20, average mutations will say a rather larger number than you'd think...