Attempting to talk with Natalie brought up Kat's dialogue instead. This occurred on Monday the 8th (Spring) in the evening around 20:00. I had just previously interacted with Kat and Kazuki in the park (in that order), then found Natalie sitting on a bench looking at her phone by the river. Attempting to interact with her brought up Kat's portrait and dialogue options. Subsequent attempts at conversation that evening with Natalie continued to bring up Kat's dialogue options. Other NPC dialogues behaved as they should. The next day, Natalie's dialogue options appeared as normal. Playing through the next two days, I haven't been able to reproduce the issue. Screenshot can be found here: https://discord.com/channels/676857688998674471/904598378904698980/931057853928726588

Thank you for the detailed description!