The problem is that there is too much pressure inside the unit.
The two holes in the back of the unit are not adequate to move the increased cfm of air being moved.
A quick fix would be to remove the power supply from inside the Avalon and having placed on top or beside of the unit.
This will permit for more CFM of air to be pushed out the back and enabling the blue fan to operate at 2300 rpm's
It may not solve the display problem however it will solve the underlying issue.
You can tell that your "Blue" fan is not spinning at its max speed when the temp sensor on the controller reports high temps of 28+
so the blue fan only opperates at 2300 rpm's? is this it's max? so replacing with a 3000rpm will be good? and better for CFM when black fans are on 4000RPM?
The problem is that the you need 1 more hole in the back in order to move the cfm of air out of the unit.
This is the issue even if you were to get another black fan running at 3600-4000rpm.