Transparency sliding bar is at full (Option Available in profile preferences). Even then terminal has solid color. It was working well a day before.
How to roll back?
I think you misunderstood the usage of the transparency sliding bar:
Sliding the bar to the Max, it applies maximum opacity, so you will end up with a solid color.
For transparent colors, slide the bar do the left, close to the Minimum, so you will have a transparent Terminal.