onAccessibilityEvent does not invoke on Android 9 Pie (API 28)

Question

My application is intended to process selected text through Accessibility. On Android API versions < 28 it works as expected: user allows downloaded service in accessibility and then app is able to process text by invoking onAccessibilityEvent(). But on Android API 28 it doesn't works at all.

<accessibility-service xmlns:android="http://schemas.android.com/apk/res/android"
    android:accessibilityEventTypes="typeViewTextSelectionChanged"
    android:accessibilityFlags="flagDefault"
    android:accessibilityFeedbackType="feedbackSpoken"
    android:notificationTimeout="100"
    android:isAccessibilityTool="false"
    android:canRetrieveWindowContent="true"
    android:settingsActivity="com.example.texthelper.MainActivity" />

<service android:name="com.example.texthelper.services.TextHelperAccessibilityService"
            android:label="@string/app_name"
            android:enabled="true"
            android:exported="true"
            android:isAccessibilityTool="false"
            android:permission="android.permission.BIND_ACCESSIBILITY_SERVICE"
            tools:targetApi="s">
            <intent-filter>
                <action android:name="android.accessibilityservice.AccessibilityService" />
            </intent-filter>

            <meta-data android:name="android.accessibilityservice" android:resource="@xml/accessibility" />
        </service>

Does anyone have an idea what is a cause?

I tried to change a android:namePackages parameter in accessibility xml file, setup a new launcher but did not help...