He can only make league minimum for first 3 years. It's in the CBA.
That's completely false.
No player is obligated to make league minimum for 3 years.
Players under 25 as of September 15 are obligated to sign an ELC. ELC money is limited, but the limit is over the league minimum and you can add bonuses on top (that will factor indirectly in cap calculations).
The term is directed by the age of the prospect.
18-21 3 years
22-23 2 years
24+ 1 year
Since Harris is turning 22 this year, he has to sign a 2-year ELC. His contract is for the league minimum, but it includes a signing bonus and performance bonuses which boost the AAV cap hit.