I just spent the better part of the last 24 hours chasing a non-problem. It is probably in the manuals somewhere, but not where I was looking. It seems that if you turn off the power to the 6700 without having a Waterfall displayed, it triggers the software into a state where the profiles that have had a Waterfall display when stored, no longer load with a Waterfall display, after you turn the radio back on. Even if you create a new Waterfall display in one profile setting, the Waterfall Persistence will not carry over to the other Profiles until you power down the radio with a Waterfall display on the current panafall. This triggers the software into the opposite state, and allows the stored Profiles to display their Waterfalls when loaded.
Solution: This sounds very confusing, and I was going in circles, but it is a non-problem, if you create a panafall and then turn off the power. After that never power down again without having a waterfall on the display.