Hi!
We’ll figure this out for ya!
There are a couple of things that could be going on here… the easiest way to figure it out would be if you could PM me or email me a few samples that I can try to convert on my machine. (My email is nate@natephotographic.com, or you should be able to click on my username to private message me).
I will say that I have seen some issues with v700/750/800/850 in Vuescan DNGs in particular, related to an issue with the embedded profile. There will be an updated profile in v2.1.
A number of users have also gotten better results using the EpsonScan method noted here, so that may be worth a try.
If you have found that Negative Lab Pro worked well with previous scenes and suddenly seems to not work well with these scenes, it could also be that the scenes themselves are trickier for Negative Lab Pro to interpret… the initial conversion are just a starting point and will often require some adjustments (though usually not as extreme as the first example).
-Nate