Ehhhh I don't know if I really saw it that way. Layer wanted to play with her close childhood friend, and she took her at her word that she could do both for now. Yes, she clearly wanted Tae to come for good, but she didn't really have any reason to believe Tae was as close to Poppin as she was to her all those years ago.
When Tae quit the band, Layer didn't push back at all, just talked with her out by the pool, gave her that fistbump on stage. When Chuu2 and Not Ibuki Mioda went to try and pull Tae back in, Layer wasn't aware, and got mad at her for doing so.
Now, I do think Layer should have realized Tae had issues with the encore, but that really felt like a heat of the moment thing.