diff --git a/app/src/main/java/info/nightscout/androidaps/plugins/constraints/bgQualityCheck/BgQualityCheckPlugin.kt b/app/src/main/java/info/nightscout/androidaps/plugins/constraints/bgQualityCheck/BgQualityCheckPlugin.kt
index 18bc5e173d..4b0c9c8e4b 100644
--- a/app/src/main/java/info/nightscout/androidaps/plugins/constraints/bgQualityCheck/BgQualityCheckPlugin.kt
+++ b/app/src/main/java/info/nightscout/androidaps/plugins/constraints/bgQualityCheck/BgQualityCheckPlugin.kt
@@ -3,8 +3,6 @@ package info.nightscout.androidaps.plugins.constraints.bgQualityCheck
 import dagger.android.HasAndroidInjector
 import info.nightscout.androidaps.R
 import info.nightscout.androidaps.interfaces.*
-import info.nightscout.shared.logging.AAPSLogger
-import info.nightscout.shared.logging.LTag
 import info.nightscout.androidaps.plugins.bus.RxBus
 import info.nightscout.androidaps.plugins.iob.iobCobCalculator.events.EventBucketedDataCreated
 import info.nightscout.androidaps.utils.DateUtil
@@ -12,11 +10,14 @@ import info.nightscout.androidaps.utils.FabricPrivacy
 import info.nightscout.androidaps.utils.T
 import info.nightscout.androidaps.utils.resources.ResourceHelper
 import info.nightscout.androidaps.utils.rx.AapsSchedulers
+import info.nightscout.shared.logging.AAPSLogger
+import info.nightscout.shared.logging.LTag
 import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.rxkotlin.plusAssign
 import javax.inject.Inject
 import javax.inject.Singleton
 import kotlin.math.abs
+import kotlin.math.min
 
 @Singleton
 class BgQualityCheckPlugin @Inject constructor(
@@ -63,23 +64,23 @@ class BgQualityCheckPlugin @Inject constructor(
     var state: State = State.UNKNOWN
     var message: String = ""
 
-    // Return false if BG values are doubled
-    @Suppress("ReplaceGetOrSet")
-    override fun isLoopInvocationAllowed(value: Constraint<Boolean>): Constraint<Boolean> {
+    // Fallback to LGS if BG values are doubled
+    override fun applyMaxIOBConstraints(maxIob: Constraint<Double>): Constraint<Double> =
         if (state == State.DOUBLED)
-            value.set(aapsLogger, false, "Doubled values in BGSource", this)
-        return value
-    }
+            maxIob.set(aapsLogger, 0.0, "Doubled values in BGSource", this)
+        else
+            maxIob
 
     @Suppress("CascadeIf")
     fun processBgData() {
         val readings = iobCobCalculator.ads.getBgReadingsDataTableCopy()
         for (i in readings.indices)
-            if (i < readings.size - 2)
+        // Deltas are calculated from last ~50 min. Detect RED state only on this interval
+            if (i < min(readings.size - 2, 10))
                 if (abs(readings[i].timestamp - readings[i + 1].timestamp) <= T.secs(20).msecs()) {
                     state = State.DOUBLED
-                    aapsLogger.debug(LTag.CORE, "BG similar. Turning on red state.\n${readings[i]}\n${readings[i+1]}")
-                    message = rh.gs(R.string.bg_too_close, dateUtil.dateAndTimeAndSecondsString(readings[i].timestamp), dateUtil.dateAndTimeAndSecondsString(readings[i+1].timestamp))
+                    aapsLogger.debug(LTag.CORE, "BG similar. Turning on red state.\n${readings[i]}\n${readings[i + 1]}")
+                    message = rh.gs(R.string.bg_too_close, dateUtil.dateAndTimeAndSecondsString(readings[i].timestamp), dateUtil.dateAndTimeAndSecondsString(readings[i + 1].timestamp))
                     return
                 }
         if (iobCobCalculator.ads.lastUsed5minCalculation == true) {