Please, please, please find a fix for this bug. ATM Corona is practically useless on my work-machine (Dual Xeon E5v3). The problem seems to get worse - now it's also showing up on max2016 (aswell as 2014), and the "short-term fixes" that worked before doesn't work anymore (reinstall Corona and reboot the PC).
Only solution for now are: change PC (to a non-dual-Xeon) or change renderer.
Please, please, please make the fixing of this this top-priority....