> > Bentonite fining improves heat stability; it doesn't affect cold stability.

I'm not sure about that in this case, there is no guarantee it's heat
stable either. This could be a pectin problem though, why not warm it
and add some PE to a small sample?

If that didn't do it would refine with more bentonite, you said it
was a light fining. Chill haze can be caused by excess protein,
anything that gets rid of excess protein would help if that is the
issue. It's easy to test, that is why fining trials are recommended.
If it's not cold stable it's probably not heat stable either.

Joe