Various forms of this article have been posted for the past several days. (Note different title so it not a double post but the articles all sources this same guy.)
In short: He is talking through his hat. He doesn’t understand the process and yes, the delegates ARE LEGALLY BOUND to vote for Trump on the first ballot and the 1237 number does matter.
No, they are not “legally” bound. Obligated by agreement between state and national parties but not bound by law.
What he really means is that if Trump gets 5 delegates over goal, the party will find away to disqualify 6 delegates. That's why Trump needs to decisively exceed the limit so the party can't disenfranchise that many votes.
-PJ