In my opinion, the crack that I've seen recently posted are architectural cracks and not structural cracks. Possible reasons ...

1. If cement bricks were used - possible insufficient curing time at the factory or at site before being used for bricklaying works. If due to that, the bricks has not fully dried, thus absorbing moisture/water from the plastering works. This causes shrinkage, hence the cracks. It is common in the past to spray water on the wall 1-2 days before plastering works commence, but I hardly see that these days, even at sites I inspect for my developer.

2. Cement/sand ratio for wall plastering works. Plasterers use lime to add to the mix. Lime helps to let the plaster stick to the wall. It eases the worker's job. Too much lime will not give the plaster strength.

3. Dowel bars or stiffiners should be provided at all 4 1/2 inch walls, where the bricks meets the column. It helps to reduce movement. If none were provided, it may be a contributing factor as well.

All in all, it's a combination of material and workmanship lacking. Feel free to add on those who have experience as well.