See OTRS ticket:

https://ticket.wikimedia.org/otrs/index.pl?Action=AgentTicketZoom;TicketID=11039662 - mentions issues syncing between devices. Also a notable suggestion about using the “Share” contextual features in iOS.

One thought is maybe once user highlights a word/phrase, taps Share in iOS contextual menu, have a Wikipedia Share extension look up the article & ability to bookmark it. Or import URLs as references or images to be shared to commons.