You know, I suspect, that I have problem only at home. Router is in 2.4GHz mode, 802.11n. I have changed chanell, It helps me not. And other devices, such as Samsung s3, galaxy tab, Samsung TV, ASUS notebook are working good. And my Redmi note2 worked good before I get new this ROM. For example, I can watch Youtube, and in moment video playback stops, speed indicator is howing only 0.5-1Kb/s. Than Wi-fi sign became light gray, like there is no signal. And in few seconds evreything gets ok.
At work I have old router working at 54Mbit with not very good signal. And link is more stable at first look. Mb because I don't use it very hard.