Who I have the same questioned this topic

Sharing my recent experience with the TURBO 2. Running on 25.22.10 (Latest Nougat 7.0 update)

My phone was working fine after the the Nougat update. In fact I was loving it! Then suddenly a few days ago, the phone started getting really warm/hot and the battery would drain when I was at work (not connected to WIFI). I noticed that the battery drain was not that drastic when I was connected to WIFI, but the minute the phone came off of WIFI and on 4gLTE, it would start warming up and losing battery like there is no tomorrow! I've tried quite a bit of things but no change. When I check under Battery Stats, the biggest drain was due to Android OS. That did not make any sense! Turns out that after a recent factory reset, I enabled the free trial for premium visual voicemail. I forgot all about it. When my phone started overheating and draining battery, I looked online to find someone reference the voicemail app. Sure enough, when I went to the voicemail app, it was waiting for me to either purchase premium voicemail or go back to basic voicemail. I switched to basic voicemail and restarted my phone. All the problems were gone! It started behaving normal again.

So folks, if for some reason you did a factory reset and opted to try the premium visual voicemail, don't forget to go back after the trial ends and switch back to basic (or buy premium)...

But it is really weird that THIS would make the phone do completely haywire and affect the battery to such a major extent!

Hope this helps someone!