Default Google Keyboard has about 200MB Traffic over night and maybe denies deep sleep

Hi guys,
with betterbatterystats i saw, that my google keyboard is causing about 200mb traffic over night.
Network (requires root)
10035 (Wifi) ( 191.0 MBytes 92,1%
I guess this is the reason why my nexus 5 is on max cpu frequency for about an hour.
Why is it causing that much traffic?
And how can i prevent it from waking up my phone?

Do you see anything else which could cause my nexus to stay awake?

Thanks for your help!