I have a JTV-59 & JTV-69 & it is - in a positive sense of course - bizarre, but I (so far) never experienced the 'Spank bug' ...
The only trouble I had a lot of 'MIDI time-outs' while trying to update with the Workbench USB device.
I solved this with updating my JTV's via my trusty old Vetta II combo - the updates run consistently without a fail - I used the 'double update' procedure as described in the 'JTV 2.0 Try This ...' - thread ...
I compared the Spank pos 2 & 4 after the update with the 'working Strat 2 & 4' files & found them to sound similar, i.e. the expected 'quack' is in the house
The only other gripe I have is that the USB device MIDI connection appears to be very flaky - I had & have a lot of instances there I can't get a connection from the JTV to the USB device (blinking red LED on the JTV side of the USB device - yes, I'm using the 1/4" jack to connect to the Vetta to listen back).
Oh yes & one of my favourite presets - Jazzbox 3 - has a noticeably lower volume on the low E string on both of my JTV's (which of course can be adjusted in workbench) - has anyone experienced this as well?
Other than that, version 2 is a definitive keeper for me - all of the the presets have significant more depth, response & detail
Thank you Line 6!