I have setup 3 CB fields similar to the country selection tutorial as follows:

Country - is a drop down single select of 3 choices
Province/State - reads in a list from a table that is based on the country selection above
City - reads in a list from a different table based on the Prov/Sate selected above
All 3 fields are Searchable

On Registration - the 3 fields work together correctly
On Profile Edit - the 3 fields work correctly
On Search Users - this is where the issue arises. All 3 fields initially show - No Preference - and I can select a Country value, but then the Prov/State field comes up blank. If I perform the search with just the Country selected, the Prov/State field is then populated based on the previous Country selection, and after adding the Prov/State and running the search, I can then select the City.
In all cases the drop downs are correctly populated, but the (Ajax?) populating of the field is not happening on the Search criteria screen.

Joomla 3.6.2
CB 2.0.15+build.2016.09.13.23.15.55.9b368327b
PHP 7.0.10
DB 5.6.31