Yeah, it is interesting. There are definitely yes voters who vote Labour. I'm not sure of the scale though (it could be as much as 30%).
That being said, I couldn't see a SNP voter switching to Labour with their position of no referendum ever. I think their position would need to be more nuanced. Which is why I expect disaffected SNP voters will just stay home.
The only caveat I'll make to that is if Scottish voters do what they did for a spell in the late 2000s. Vote Labour at WM & SNP at Holyrood. I think that particular calculus died in 2015 though.
As you say, it's certainly not dull.