[Lollipop]WiFi Turns off at idle

In our Xperia V Thread, everyone on all lollipop roms (all based on CM) have WiFi disconnecting issue when phone is idle.

"Keep WiFi on during sleep" is set to "Always"

I also entered this command in terminal but it didn't helped either.

Code:

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settings put global wifi_sleep_policy 2

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What should we do? Is there any possible fixes?