Food for thought: from page 15 onwards, when Rika is speaking with Takuya, I assume it'd be in Japanese instead of English, so theoretically they can speak about their "secret" openly in front of Claudia without her knowing what's going on. Unless it's revealed in the future that Claudia knew Japanese all along, in which case more plots emerge. I wouldn't be surprised at, or mind that kind of twist tbh.
Also, there's no dialogue spoken in this chapter to "misunderstand" by Rika eavesdropping like in a lot of western romcoms (because Takuya is ideally friendly and hospitable), which is great because I hate those kind of cliche situations, but I wonder if Rika can understand much English as well, as she didn't react with the conversation between Claudia and Takuya much.