It's a delamination. Fabricator/installer error.

The heat and humidity from the dishwasher also likely contributed to this problem.

kitchen was under renovation, and I have not used the kitchen. Tape just came off only to find this.

In that case, install error as Joseph noted.

It looks like the lamenated edge overlaps…??? photo enlarged

100% installer error

Could this be what the chip on the seams would lead to? I ask because there are other areas with chips on the seams, and I worry this will too happen in those areas. Or, is it that chips dont always lead to cracks like this?

Call the installers back to correct it there is really nothing else we can do. I too see the overlap which makes no sense so maybe start there .

I don't think it's an overlap it's just that the filler that bridges the miter area is still adhered to the horizontal piece of porcelain ablove nad to the lft of the delamination about a inch or so.

And installer error - they should be able to fix.