After seeing Watashi "take responsibility" in episode 6 I also started thinking the story isn't going in a normal chronological order, it just feels too weird to have her hair cut twice, especially if we assume that the episodes are going in a chronological order, which means Grandfather would already know that Watashi can easily regrow her hair back with the fairy products, and there won't be much of a point calling it taking responsibility.
I took the liberty of doing a couple of screenshots from ep 1 and 5 (she tied her hair midway in 5 so no point in screen caps from 6)
Episode 1:

Episode 5:

It is more than possible that it's just an animation slip up, and I should do more screenshots and pay closer attention to the dialogue between the episodes to back this up better, but it does seem that time isn't exactly moving in one direction between these episodes.
Pretty sure opening the novel will give answers now, but no fun in doing that, so let's discuss this.