Weird read:
Flower has felt the need to claim something as scum because that is what people think she does as town.
She was somewhat worried about that last time we scummed together (a mash on mu, I think).
Saka mocking Flower for claiming d1 could be a way to give her an excuse not to do that and make her life easier as partners.
In part because her townread on Saka afterwards is no good.
I don't know if I believe in this, but I am in a "see something, say something" mood.