UPVC door and window cracks

[Josh1208]

I'm just about to start decorating the kitchen and bathroom in a new build property (about 5 1/2 years old)

I've noticed that the french doors in the kitchen and the window in the bathroom have some cracks running around it. It's not on the immediate join between the wall and the door/window, it's about 10mm in from the door/window. If I apply some pressure to either the door/window, the crack does increase by a mm, so it is very slightly flexible.

I've attached some images of the cracks, what would the advice be to cover these up?

 

[sxturbo]

It's just where the plaster has been joins to the window,

The opening and closing has caused the plaster to crack.

Dig out the cracks slightly and apply a flexible filler.