It's a bug.
In the last update (or the one before), the dev introduced the option to avoid certain girls.
With Lana it's when we see her in front of the MC's house when he collects the furniture. This is where we have the option of avoiding Lana or not.
I think the bug comes from there since before this addition in the game, I was able to do yoga and go to see her in the evening.
I have no solution, apart from testing if it's just an inversion, and therefore we would have to choose the option to talk to her later or to ignore her, to be able to see her.