I don’t have that plugin personally, but did have a few questions. Does the problem happen in both Windows 7 32 bit and 64 bit? Do you have the same issue with any other plugins? Before Cubase 8, what other versions of Cubase did you have on the system (and does the problem occur there)?
I would suggest installing the 32 bit version of Cubase to see if the issue persists there. The 32 bit version will not affect the 64 bit version. Have you contacted Waves regarding the issue? If the Instrument track has Halion Sonic SE on it, does the crash also occur?
If you load a stereo audio track, does the plugin have any trouble?
Win 7 64 Bit Butch Vig Stereo Version on Instrument Track Sampletank 3.
Insert Butch Vig, no problem, no crash here…