Please correct me if I'm wrong, but from what I gathered,
The blue line is showdown winnings. Surprisingly, it's what you've won in showdowns.
The red line is what you're supposed to have won in showdowns. So you basically started winning a lot of coinflips (or worse) near 1.8k hands, but overall your luck is pretty normal.
The green line is your actual winnings, so that's counting the pots you've won or lost _without_ a showdown. So basically (I think) you're losing way too many small pots.
But since I'm no good at explaining, I found this in a blog post:
The green line shows your hands that did not go to showdown compared to your actual winnings. How to interpret it depends on your play style and other factors. Like if you are playing with a bunch of donks and play quite tight fit-or-fold poker your green line will be below the blue line on average. This also applies to calling IP with good draws and folding if you miss. If you bluff in bad spots too often your green line will also be much lower.
If it's above the blue line it can also mean different things. It can either mean you play your draws aggressive, pick good spots to bluff, but can also mean you fail at getting your good hands to showdown enough.