Husky marking territory?

Hi. Need feedback on this scenario.

One of my grey (I have 2) Siberian Huskies are peeing and pooing on the carpet in my second bedroom. Both are female. One is 4 and I've had her since Nov 2025, and the other is 8 yo. Had her since 2021. Anyway, normally the 8 year old sleeps in the spare bedroom, but lately when she goes out to pee, the 4 yo one, Lana, goes and sleeps on the bed. Sometime later in the night, she gets up to pee and sometimes poo in there, and am sure now thinks it's her toilet room when it's raining outside.

My older more gentler one doesn't go back in that room when she sees Lana go in there. Too crowded I guess.

They get along great, and are bonded.

Thoughts as to what's going on?