When I update spree config via admin panel Spree::Config[some_key] = some_value it overwrites the value in a spree_preferences table, but also store previous versions of value and use all these versions.
Rails.cache.clear do not help. But restart a unicorn helped me.
Where are these versions stored? How can I explicitly reset the cached values in the code?
The problem was in the caching of unicorn workers.