Unsportsmanlike Conduct Question

[reddevil19]

Hello all. I am the PA announcer for a JC football team, and last night we had penalty enforcement that didn't seem quite right to any of us in the box.

On a 2nd down, the defense (home team) sacked the QB, which would have made it 3rd and 17. The sacker however was flagged for unsportsmanlike conduct. The penalty was enforced, but the down was still 3rd, with 2 yards to go. We all thought that was an automatic 1st down, fairly certain that we have seen unsportsmanlike conducts result in automatic first down's in the past in that situation where the 15 yds wouldn't make a 1st on its own.

Game is played with NCAA rules. Was this correct? Also, is there a difference in High School NF rules? Thanks for your responses.