The timestamp on the camcorder recording Caldwell's confession is "2021/04/21"; meaning April 21, 2021. In the first episode, Dexter's wall calendar revealed it to be December 2021. Furthermore, every episode before and after have clearly established the events as taking place during Christmas time. It most definitely is NOT April.
Orthopedic titanium implants are a dull darker gray color. The screws that Kurt sent as a threat to Dexter are shiny like chrome. Clearly they are stainless steel screws, not titanium.
Harrison was around one-year-old when his mother, Rita, was murdered. A human' earliest memories begin at age 2.5. There is no way he could 'remember everything' about the murder.
The DNA sample is said to be a 67% match for the suspect. The suspect explains how the DNA actually belongs to his father. However, if the DNA was, in fact, the father's then the suspect son would be, at most, a 50% match to the DNA sample. If the son's DNA is a 67% match for the sample DNA, then the father could not be the source of the sample DNA.
A lead bullet will not destroy a steel padlock.
Referring to the sample of flesh recovered from Iris's body, Dexter says, "Unless whoever did this is already in the system, there may not be enough left to test it against multiple subjects." You wouldn't need to do multiple DNA tests on the sample. You'd test it once and get a DNA profile. You could then compare this to millions of other profiles if necessary.