He thought Rose was a old woman... And I'm pretty sure Harij was already starting to look after her even before he saw her bathing in the lake. In the first place, that incident happened when Harij was on his way to give Rose some freshly baked bread, since he's worried about the old witch who has only been consuming lettuce (which leading to him accidentally seeing her bathing in the lake, and finding out that she's not a old woman but actually a young woman). Him being worried and buying that bread for her (even before he saw her naked lol) shows that he already have a interest in her...
I'm guessing that incident will still happen, since that happened right after Harij found out about her eating habits. Honestly, I prefer if they leave that incident out or if they'll include it anyway at least let her not be naked. xD