Altbeacon - Samsung Galaxy s9 not ranging beacons as expected when locked and power cable unplugged - altbeacon

Question

I'm using the Altbeacon library and implementing the foreground service to allow for faster ranging. My app is designed to send a notification to the user whenever a matching beacon is ranged. The goal is that this happens no matter what, phone locked, unlocked, app open, app closed, and app cleared from task manager.
The app works as expected with a Samsung Galaxy s7 running Android 8.0. The issue I'm experiencing with the Samsung Galaxy s9 running Android 8.0, is when the power button is pressed to lock the phone. The phone no longer receives the notifications as often as it should, as if the foreground beacon scanning is being blocked.
The device sending the beacons can transmit a new beacon continuously at a 25ms rate for 12 seconds, for testing purposes, at the end of the 12 seconds it is set to repeat that process. The user should receive a new notification every 12 seconds, however the s9 may only receive 1 notification and then 5 could be missed before is sees another. The s7 will receive every single notification as expected.
The background scan rate is set to scan for 1.1 secs and wait for 10 seconds. I wish I could provide logs for the issue but when the phone is plugged in the issue doesn't occur, so I can't really pin point why the s9 would be acting this way when the s7 doesn't. I assume it has to be something with doze mode or sleep mode since when the power cord is plugged in, the s9 receives all the notifications as expected. Those are the only two phones I have been able to test so I don't know if it is also an issue with the s8.
What could be causing the s9 to not range the same as the s7 when locked by the power button? If the phone just goes to sleep on its own, it acts the same as if the power button were pressed to put it to sleep. Code snippet below.
Thanks!
mBeaconManager = BeaconManager.getInstanceForApplication(this.getApplicationContext());
set_forground_notification(true);
logManager.setLogger(Loggers.verboseLogger());
logManager.setVerboseLoggingEnabled(true);
mBeaconManager.setAndroidLScanningDisabled(false); // Setting to false allows low latency scanning
mBeaconManager.setRegionStatePersistenceEnabled(false);
mBeaconManager.setBackgroundScanPeriod(1100);
mBeaconManager.setForegroundScanPeriod(1100);
mBeaconManager.setForegroundBetweenScanPeriod(2000);
mBeaconManager.setBackgroundBetweenScanPeriod(10000);
mBeaconManager.setBackgroundMode(true); // this is being set to true here so that on app termination
// or reboot when the app starts back up because of the service, the scanning period
// is set to background and not foreground
private void set_forground_notification(boolean post)
{
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
if (post) {
String CHANNEL_ID = "Scanning_for_device";
CharSequence name = "Scanning_for_device";
NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, android.app.NotificationManager.IMPORTANCE_HIGH);
mChannel.setShowBadge(false);
mChannel.setSound(null,null);
NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(this, CHANNEL_ID)
.setSmallIcon(R.drawable.ic_foreground_logo)
.setContentTitle("Scanning for Device")
.setSound(null)
.setOnlyAlertOnce(true);
Intent intent = new Intent(this, MainActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(
this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT
);
mBuilder.setContentIntent(pendingIntent);
android.app.NotificationManager mNotificationManager =
(android.app.NotificationManager) this.getSystemService(Context.NOTIFICATION_SERVICE);
mNotificationManager.createNotificationChannel(mChannel);
// sends foreground notification and starts foreground scanning?
mBeaconManager.enableForegroundServiceScanning(mBuilder.build(), 457);
} else {
// removes foreground notification and stops foreground scanning?
mBeaconManager.disableForegroundServiceScanning();
}
}
}