Rendered surfaces on MODERN timberframe houses is achived by attaching vertical battens to the outside of the timber inner skin, then nailing a sheet material to the battens and putting the render subsurface onto that (then final finishing). I suspect that a minor movement in the inner frame structurally has caused minor movement in two or more sheets, which has cracked the joints between two sheets. Timberframes always move a bit as the seasons change.
You can fill it with cement/sand mix and repaint if you wish to, but it is likely to come back again, but I doubt that it will get worse. It is not structurally important as the strength of the structure resides in the timberframe, which is the inner skin.
The bottom half of brick is not structurally attached to the timberframe, by the way - it has its own foundations on which it sits, being tied to the inner skin using stainless-steel brick ties.
That is the normal way modern timberframe is built.