I got the same failure also, it always disconnected access point after resume from sleep. I need to toggle my wifi off/on again, then it became normal.
But I found something, if I uncheck "Allow computer to turn off this device to save power" from power management tab from device manager for Intel AC 7260.
It can auto connect with my access point, it just needs to take around 1 ~ 2 mins to auto re-connect.
Can you reproduce my case? by the way, I use latest driver v17.0.5.