Playing without Nathan Cleary, the Panthers appeared rudderless at times in the six-point victory over the struggling Broncos.
Only a penalty goal and a two-point field goal would come out of the first half, with Penrith struggling to put their unfancied opposition away.
The second half brought about a change of fortunes, although Penrith still would only go on to win by six points. However, it was the eighth-minute incident which left Cleary confused.
Isaah Yeo, attacking the tryline, was hit high on the jaw by Flegler. It resulted in Yeo being knocked unconscious on his way to the ground, and the New South Wales Origin lock forward was unable to participate any further in the game.
While Flegler was sent to the sin bin, allowing Penrith to activate Jaeman Salmon as their 18th man, Cleary questioned why it wasn't a send off.
"He was knocked out as soon as he hit him," Cleary said.
"It's an illegal act, that's why [Flegler] got sent to the bin, so I don't know what you’ve got to do to get sent off. It's just my opinion.
"If it was Magic Round, he would have been sent off."
The NRL's high tackle crackdown has confused in recent weeks, with NRL officials taking a far more lenient approach to contact above the shoulders than seen in Round 10, when the crackdown first began.
Send offs have become almost non-existent in recent weeks.
"I don't know, we haven't seen [a send off] for a bit. But clearly a high tackle, knocks him out on contact, you lose your captain and one of your best players for the game," Cleary said.
Penrith are fortunate to have a seven-day turnaround ahead of their top of the table clash with the Melbourne Storm next week, leaving Yeo a chance of being okay to play.