It is a known problem (I think discussed somewhere else) were the texture coordinates do not align between one wall face and the adjoining walls end. This is due to the new Priority based connections, where walls no longer mitre. Also each wall has its own coordinate base - ie to the individual element, so when you move or drag a wall the textures keep aligned with the element.
One way to try and solve this is by aligning the texture of the wall face to try and match the wall end - may work vice versa. If this is just one elevation, you could modify the wall junction order so that the slightly shorter wall then extends pasts the other wall - so you don't see the exposed end in that elevation (but then you'd have the same issue on the other elevation).
We have been actively working on a solution - though it has proved to be more complex than one might have thought.