door weatherstrippping leak

Hi, I have a 2015 access cab that seems to have defective weatherstripping on the driver's door. At the top, near the rear corner, the material seems to be thinner. here are a few photos:





When the door is shut and it rains, water seems to pool in this area circled in red. So when I open the door, water falls directly on my seat. Also, it seems like water is getting past this weatherstripping, here are a few more photos from after some rain:




The passenger side doesn't get wet like this. does this seem like a defect? How easy is it to replace this part?

thanks.