I’ve uptadeted to your latest build (1.8.25) and this issue started to appear.
when I am using the mouse wheel to zoom in, the screen start to blink.
This wasn’t happening on your previous version that i used (i think 1.8.17).
during the zoom in\out the state is changing for some of the objects on the graph.
On all major browsers: FireFox, IE11 and Chrome.
Running on Windows 10.
Here are the changes that i made for zooming:
myDiagram.toolManager.mouseWheelBehavior = go.ToolManager.WheelZoom;
myDiagram.commandHandler.zoomFactor = 1.15;