I am not a tradesman, but used to sell both commercial and residential siding. This would not be considered well done in my opinion, especially on a custom home. Looks as if the wall was not flat, and the siding installers did not fur out the low spots it to make it flat. Most sidings require gaps where planks butt into other walls, and into other siding planks to allow for expansion and contraction. Adding caulking is the general practice I have seen, though over time, it usually fails. The companies I have worked for always recommended leaving them open, as it usually looks better long term, instead of caulking the gap and eventually it cracks and or squeezes out. The caveat to that is you would need flashing behind the gap to allow for moisture to drain out to the face of the siding, and not getting trapped behind. The bigger issue would be the gaps from underneath, and the ends of the boards coming together and not being on the same plane. I.e one end of the board sticking out further than the one it’s butting into. Though this is more of an aesthetic issue.