Error invokeMethod onImpressionSucces not implemented

[92sajid110]

java.lang.Error: Critical Error: invokeMethod onImpressionSuccess notImplemented
E/AndroidRuntime(19536): at com.ironSource.ironsource_mediation.IronSourceMediationPlugin$invokeChannelMethod$1$1.notImplemented(IronSourceMediationPlugin.kt:760)
E/AndroidRuntime(19536): at io.flutter.plugin.common.MethodChannel$IncomingResultHandler.reply(MethodChannel.java:236)
E/AndroidRuntime(19536): at io.flutter.embedding.engine.dart.DartMessenger.handlePlatformMessageResponse(DartMessenger.java:375)
E/AndroidRuntime(19536): at io.flutter.embedding.engine.FlutterJNI.handlePlatformMessageResponse(FlutterJNI.java:1003)
E/AndroidRuntime(19536): at android.os.MessageQueue.nativePollOnce(Native Method)
E/AndroidRuntime(19536): at android.os.MessageQueue.next(MessageQueue.java:326)
E/AndroidRuntime(19536): at android.os.Looper.loop(Looper.java:160)
E/AndroidRuntime(19536): at android.app.ActivityThread.main(ActivityThread.java:6669)
E/AndroidRuntime(19536): at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime(19536): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
E/AndroidRuntime(19536): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

first time rewarded ads shows successfully
on second time it crashes with above error.