This happens with both the new app and the classic app. I have tried resetting the V2 hub and even deleting the device and re-pairing it (a Leviton Z-wave wall switch).
I have another identical wall switch 8 foot and away and the app always syncs immediately with the device status.
Interestingly, my Smartthings button and Amazon Echo immediately turn the device on/off as expected.
After a longggggg delay, the app finally show the correct status.
Does anyone have a clue why this delay occurs. The problem seems to disappear for days or weeks then crops up again.