Open any prebuilt scene (other than console based output)
Start scene
Glitch town.
Profit?
How did the result differ from what you expected?:
Self explanatory.
When did you first notice this bug?:
Downloaded 0.4.9, immediately occurs when starting scene.
Have you found a workaround?:
Use a computer with a non-Radeon GPU (or, if your MacBook has multiple GPUs, switch to the non-Radeon GPU).
Other notes:
The scene actually executes properly, you can see it between the glitch frames, for example the tennis scene works, but it's picking up other graphics data from somewhere.