Thank you, Kelmych. Turns out it's not really a big deal.
Found a detailed answer here: https://www.loverslab.com/topic/20808-its-almost-ok-but-the-start-of-a-new-game-i-create-a-new-save-to-save-in-wrye-bash-are-marked-in-orange-why-does-this-happen/ Also here (even though it's for Oblivion): https://forums.nexusmods.com/index.php?/topic/153677-save-files-in-wrye-bash-are-orange-after-changes/
acindron's post in Why are my save files orange in Wrye Bash? was marked as the answer