Please pardon my perspicaciousness 
Per the pictograph popup, I presume picking the "persistent" preference of perspective properties/parameters provides persistence to the value of properties, not the properties proper.
The value of this property will not be saved with the view
However, if I disable the "persistent" option on custom properties/view parameters, then close and re-open the view, the custom properties/view parameters disappear. If I have the custom properties/view parameters bound, they seem to have disappeared on the initial (re)loading of the view, but if I click another component in the tree, and then back to the view, the bound custom properties/view parameters reappear. Of course input view parameters can't be bound, so they have properly disappeared.
Saving to the gateway with the missing properties/parameters doesn't seem to cause a problem (like it would if the bindings had been deleted).
If i manually add one of the missing (bound) properties, all the other bound properties reappear.
I must manually re-add all of the missing, unbound properties.
This seems reminiscent of a very similar early beta problem (not related to the 'persistent' preference though)
Perhaps the preceding peculiarity presents a problem?
I can upload a video/gif if desired.
8.0.10
EDIT: of course after I post, i find similar threads despite searching beforehand. Perhaps merge this with the other threads?