Android deep link nested activity back stack not working

Question

I have a deep link into activity A in my app. From activity A, user can go to activity B. When user presses back button in activity B, I expect them to land back in activity A, the start of the deep link. But instead, users land back into location of deeplink before activity A.

Why is one level in the stack skipped?

Here is my deeplink code for activity A:

<activity
            android:name=".group.ActivityA"
            android:label="@string/activity_title">
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />
                <data
                    android:host="activityA"
                    android:pathPrefix=""
                    android:scheme="appname" />

                <category android:name="android.intent.category.DEFAULT" />
                <category android:name="android.intent.category.BROWSABLE" />
            </intent-filter>
        </activity>

Expected flow: deeplink root-> Activity A -> Activity B, back -> activity A -> deeplink root

Actual flow: deeplink root-> Activity A -> Activity B, back -> deeplink root

Note: This is an in-app deep link. (deeplink is shown in my app itself)