I love this chapter because on one hand, Mai is really trying to put a boundary in place here, essentialy staking her claim to get Ajisai to back off.
But then in doing do she forces the issue on Ajisai who hasn't actually thought her feelings through yet, and who as a result both fully realises she's in love with Rena and also it looks like is finally going to start putting herself first and become a true rival to Mai.
wait what ?
let me re read for a sec........
alrite, She's asking about how ajisai ran away from home
how renako doing everything because she likes ajisai
How mai already confessed and renako still didnt give clear answer
how she told everything because ajisai probably in love with renako already
how ajisai decide that staying friend is the best for her
and how Mai just nod with sad/dissapointed expression
i don't think Mai want ajisai to back off or any of that, she just recognized her as rival. it's simple as that
unless i missed something from LN which i didnt read