Siding breaks above penetrations like this dryer vent invite water right into the penetration hole and could allow water to leak inside the house.
The correct way to deal with penetrations is to use a split mounting block. Beveled to drain downward, the split is also sealed with caulk.
Fiber-cement boards shouldn't be butted up against the trim, but should be left 1/8 inch short to allow for expansion. Th gap will allow for a caulk joint that will expand and contract with dimensional changes in the siding boards. Without the gap, you get a flat strip of caulk that is prone to peeling off.
Whoever installed this siding neglected to prime the cut ends - a requirement of the manufacturer's installation instructions, which building codes mandate must be followed.
Exposed edges near the base of a wall particularly need to be primed to protect them from water that runs down the face or that splashes up.
The gap above header flashing should remain uncaulked, but should be at least 1/4-inch. This gap is much too small.
Per the manufacturer's installation instructions and the Evaluation Services Report (which take precedence over prescriptive buildin codes), there should be at least 1 inch to 2 inches of clearance between the siding boards and the porch surface.
The installers brought the siding down onto the roof surface, though there should be 1 inch to 2 inches of clearance for this brand of siding.