Also, it’s not shown here, but the Installation instructions call for inside corners to have housewrap, and 90 degree sheet metal (3" or 4" flanges) installed in the corner behind the corner trim. Don’t expect to actually see it, though. I’ve never seen a set of installation instructions on an actual job.
Also, the instructions call for ¼" gaps to be left above window and door head flashing and these gaps should NOT be caulked, so that any water getting behind the siding can find a way out. Kinda looks like they are caulked in your photo.
I did a lot of research on HardiPlank for the House of Horrors in order to make sure that the example that was supposed to be correct was actually correct. I gave the instructions to the installer. He installed the trim around the window OK, but then he butted the siding tight to the trim. This stuff is installed wrong all the time.