Select instrument, create beam. In the inspector change the 3D offset of the Z co-ordinate. Crash. Or change 3D offset in the inspector and then create beam. Crash.
The crash report shows what happened but it is the result of an earlier error. After looking at possibilities, it is likely that changing the Z offset put the height of the light at the beam plane. This causes a division by zero. This eventually results in an assertion failure. This possibility is trapped in v3.2.5.