Synth attenuation broken with 4.18 update?

Something strange seems to be happening to synths after I installed the update to 4.18. There’s something wrong with attenuation - the orange attenuation spheres disappear if I change any attenuation settings. It seems that starting the level and clicking on the blueprint makes the attenuation spheres visible again but it’s impossible to work with them, as the then disappear when any settings are changed… any ideas?