As far as the Orange and Blue, I have no idea, I don't think I have ever noticed that. I had typed up a bit about my guessing that it was fighter class related, but I asked in the Discord and got an answer about ten minutes later from Chyos. I didn't even tagged him, impressed with the fast reply. Which was:
"you had the right guess, it is because of class related attributes. however when I originally set them up I didn't go into deep settings with all classes. so this means for the hunter I did it, for the others I pretty mutch patched it together so that it works (because on existing saves you can't change the main attributes without breaking saves). Something I should probably put on my to do list for the next savebreaking update (in the far future).
but it doesn't have any consequences other than the color of the bar"
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As far as deterioration your talents don't deteriorate, ever. I am wondering what has led you to think that they do? They are just ways to strengthen each party member, that's why you spend them. Like a lot of RPG's when you level up, you get a skill / talent point to spend to customize your character. Talent points spent never go away.
(Yes, some quests require to level certain talents to complete the quest.)
Thank you so much for the reply and clarification as for the deterioation question its because at certain times i've notice when playing that at the bottom of the screen there would be a prompt saying that one of my skills/ talents would lose a level so i assumed that if i didnt use them they would go down over time.For example , dexteriety going down , hunting and so on I saw another reply earlier and according to him the reason for this is that there is a temporary talent buff because of food hence why sometimes these skills go down and it helped me clarified why this phenomenon would happen