Already found a bug: NinaLake1 and NinaLake2 scenes have been defined twice in script.rpy, first for chapter 5 and later for chapter6.
The later ones overwrite the previous ones, so now in chapter 5 those 2 images have been replaced with chapter 6 images.
Attached fix adds 2 new image definitions for chapter 5 Nina lake scene in a separate file and replaces "game/CH5 Scenes 6-17 Wakeup - Elise Double - Mia Pickup - Party Start - Party Outside - Party End - Evelyn.rpy" file with a new one that uses these 2 images instead of the 2 chapter 6 images.
Extract zip into the main (root) folder of the game where the game launcher Love_Season.exe and Love_Season.sh files are.