why android navigation similar deep links for one destination not working correctly?

in one of my destinations, I have 3 deeplinks like this:

<deepLink
    android:id="@+id/deeplink_one"
    app:uri="https://example.com/{first}/" />

<deepLink
    android:id="@+id/deeplink_two"
    app:uri="https://example.com/{first}/{second}/" />

<deepLink
    android:id="@+id/deeplink_three"
    app:uri="https://example.com/{first}/{second}/{third}/" />

and results are weird:

for https://example.com/item1/, placeholders fill like this:

first = "item1" // that is not weird
second = null
third = null

for https://example.com/item1/item2/, like this:

first = "item1/item2" // <---- that is not what I want
second = null
third = null

and for https://example.com/item1/item2/item3/, like this:

first = "item1/item2/item3" // <---- not wanted, too
second = null
third = null

What am I doing or expecting wrong?