There is at least one topic on this, but it is not getting much traction despite being very easy to replicate. I’m talking about actual aircraft performance, not system (FPS), and it doesn’t make a difference if there are icing conditions or not.
I’ve filed a zendesk ticket, excerpt below:
When flying through clouds, airspeed reduces by at least 10 knots compared to the airspeed when not in the clouds. Occurs in both icing and NON icing conditions.
In real life, in non icing conditions, there is no noticeable airspeed difference when flying through clouds.
If having the same issue, please vote.