It is production welding, i have seen the same thing on custom built frames and many production frames including Bridgestones. Quality control is a time based and therefore a factor in the final cost if the product. Therefore you see a lot of this. Paint choice can also hide a lot too, this is why powder coating is great as it is heavier on average when compared to wet paint. But then I have stripped a cycle art painted frame that had an unbelievably thick primer/filler layer under the paint. There is a lot to the term what you see and do not see. Since frames are painted your assumptions of quality is based on that aspect of the frame not the actual important bits that natter more. Since I an of an earlier generation of cyclists and the same for my indoctrination in to building regardless of the appearance of a Tig joint I view it negatively, since the nature of Tig is a shortcut joining process.