Seems strange to me, but #Xabber does not implement https://xmpp.org/extensions/xep-0191.html

I'm looking through some XEPs, looking for one that specifies that all requests sent from non-roster JIDs can be rejected.

(Yes, I use Xabber, not #Conversations, as my #XMPP client on #Android. Every time I try to use Conversations, I have a very strong reaction and end up deleting it. I think the most recent time is permanent. I just can't stand it.)