interestingly I was watching a programme on the Yom Kimpur war and they were saying Syria kept building up forces then reducing them at the border until the actual invasion when the Israelis were lulled into a false sense of security allowing people to go on leave having seen it many times before. It struck me as rather like what Russia is doing.
Putin himself has form for this, announcing Russia's withdrawal from Syria on more than one occasion.
I don't think there is anything 'authentic' about A Van's posts - just part of his FSB day job.
No doubt, he can explain the high number of Putin opponents who happen to fall out of windows, Russian agents poisoning dissidents in the UK and elsewhere, MH17,...the list goes on.