That sounds like you found a bug! Can you let me know around which day did that start happening for you? (And also which cases did you finish?)
Viewing post in Null Metal Detective: Tactical Schedule Management comments
It started on Friday I assume since I had just hung out with Tai on Wednesday. I did the case of the Ring and the Raven in week one and finished it and had finished up the case with Ribbitter on week 2 and then the cutscene was the same as the one with Tai and it kept happening even on week 3 where I had chosen to check on Tai.