I only see his profile picture but no background image on his profile on 3 clients and same when viewing it through nostr.build and your NIP-05 resolves fine for me. So does his. But yeah, no background image on both profiles. For me anyway
nostr:npub18tqatnhdjza2vhfmf2grgx3yxhzmzw4y88t092xw26aygffmha0scdwmsa - does my background image and nip-05 render properly for you? It does on his. Everything works fine on his phone. Just not mine
Discussion
Yeah he hasn't uploaded a bg image yet, I'm gonna move mine to a folder on my server soon - still weird, but the only thing I can think now is it's mobile specific