WhatsApp MessageService is always killed shortly after exiting the app

A couple of days ago I noticed that I no longer receive WhatsApp messages until I manually start the app, which is when the pending messages get delivered all at once. I started my investigation by monitoring the com.whatsapp.messaging.MessageService in the Application Manager. Here's what it looks like at first, after I exit WhatsApp: And here's what it looks like a few minutes later: It looks like the MessageService either quit, or it was terminated. To verify this, I checked with adb. I can see the service at first: $ adb shell dumpsys activity services | grep wh * ServiceRecord{43deec28 u0 com.whatsapp/.messaging.MessageService} intent={act=com.whatsapp.messaging.MessageService.START cmp=com.whatsapp/.messaging.MessageService} packageName=com.whatsapp processName=com.whatsapp baseDir=/data/app/com.whatsapp-1.apk dataDir=/data/data/com.whatsapp app=ProcessRecord{42d19f90 10037:com.whatsapp/u0a10187} But then this service disappears, even though the main process is still running: $ adb shell ps | grep wh u0_a187 10037 215 988084 78996 ffffffff 00000000 S com.whatsapp The service does not get terminated at the same time. I have seen it killed as early as 6 minutes after exiting WhatsApp, and as late at 11 minutes. But in the vast majority of cases, it is terminated some time on the 8th minute. I have carefully examined the logcat during the moment of service termination with the following logcat query, which I believe silences only the stuff I don't care about: adb logcat -v time LightSensor:s LightsService:s SensorService:s SensorManager:s STATUSBAR-BatteryController:s BatteryService:s HeadsetStateMachine:s android.widget.GridLayout:s MP-Decision:s SignalStrength:s McClient:s McDaemon:s QcrilMsgTunnelSocket:s | grep -v ss_tz_mobicore | grep -v ss_daemon I was not able to see anything in the logs that would hint at what happened to the service. Did it quit? Did something kill it? How can I find out? I thought that maybe the service was terminated b/c the OS was low on RAM, but this does not appear to be so. Here's the RAM at the moment of termination: $ adb shell free -m total used free shared buffers Mem: 1821 1587 234 0 75 -/+ buffers: 1511 310 Swap: 399 134 265 While working on this issue, I have used Titanium Backup to freeze all apps that might interfere with normal operation of WhatsApp, so these are the apps I froze: - Greenify - Amplify - XPrivacy I also turned off "Per App Hacking", which is an Xposed Module. Any ideas on how I can learn more about why MessageService is being terminated? **EDIT 1**: Is it possible that MessageService is supposed to get terminated, and that WhatsApp relies on GCM to be notified when there are new messages?