I have one solution.try a VPN application from Google store and see the result. I think this is something about user privacy, that's the reason Samsung is denying this problem
I have an S9+ and been havind delayed notifications since Adroid Pie update. All was well untill then.
things i have tried and did NOT fix the issue:
1. Clear cache partition
2. Remove apps for the Sleeping app list
3. Disable battery optimisation for apps
4. Turn off adaptive battery
5. Factory reset. Twice.
6. Turn off sleeping apps function
Issue occures on wifi and mobile data as well. If there not a general delay on all apps at once. If Whatapp is delayed Messenger might work well. Issue is occuring randomly form time frame point of view. There can be half a day that an app works well, the 2nd half of the day delays might occure. Have not identified apps that are allowed to push notification not to be affectred by this issue. Girlfriend has an S9 and the issue is affecting her device as well. Other friends using other models such as Note 9, Note 8 and S10+ show this behaviour. In the S1O+ case he is considering returning the phone. All mentioned devices are using Android Pie.
Hope this helps and Samsung is looking for a fix.
The worst part is not knowing whether this delay occurs on other Android devices as well such as Huawei, Xiaomi, Sony etc. It's easy for me to switch to another phone manufacturer, but I don't know if that will help.
Hey guys, this worked for me. Go to settings, apps, clink on the three dotted lines on the right, special access then optimise battery usage. You'll see apps that are not optimised. Click on the downward facing arrow then all apps. That done, uncheck all the apps you want to receive instant notifications. Hope this helps, cheers!
I am using Galaxy Note 9 with Android Pie and facing problem with delayed notifications. I tried all suggested fixes and none of them didn't help. I turn off battery optimization for Gmail, Viber and Slack; turn off adaptive battery; turn off Put unused apps to sleep; turn off Auto disable unused apps; switch to High performance Power Mode; turn off Auto optimization for apps. None of these settings didn't help.