Russian ruble down for no reason

I don't have an explanation to the recent ruble downfall to the usd other than intentional devaluation of its currency by the Russian Central Bank (RCB).
As Russia faces a period of deflation, it appears that instead if lowering interest rates, RCB lowered the ruble itself to both usd and the (falling) euro by about 5-6%.
I find this quiet intervention disturbing as easing ruble hurts common people and their spendings. Not to mention that such actions must be brought forward before the public in advance.
Meanwhile usd index stays rather stable around 77,5  and Brent oil well above budget-prospected 95$/br, at 110+