Lee looked to have begun the day in the same form which had taken him to second place on the leaderboard going into today's final round.
Two birdies from the opening three holes immediately launched Lee to within one shot of overnight leader Taylor Pendrith.
However, a bogey and a string of pars signified a plateauing of Lee's score that, nonetheless, still saw him take the lead after 11 holes as Pendrith faded at the tail-end of the front nine.
Lee then experienced an inexplicable collapse as, over the course of holes 12 to 14, Lee went double-bogey, bogey, bogey to drop to three-over for the round and outside the top five.
The period caused NBC's commentator's to observe that: "someone jumped in his body for about 45 minutes, now he's back."
The bounce-back mentioned was three straight birdies over holes 15, 16 and 17 as Lee's body-language and form returned.
With just one hole to play, Lee trailed Herbert by one shot and needed yet another birdie to be in the running to secure an ongoing fulltime card on the PGA Tour.
Lee gave it everything off the tee as he visibly muscled the ball up the fairway. Unfortunately, the ball landed in the rough, on a steep downward lie, forcing him to play a dicey second shot which took him to another section of rough to the left of the green.
That left Lee needing a chip-in to stay in contention and, while the shot was a good one, it slipped by the pin and the best he could do was secure par and a share of second place.
Lee needed to finish in outright second or better to secure an extended spot on the PGA Tour's medical extension card.
As it is, Lee currently competes via a minor medical extension due to a shoulder injury last season. By securing more than 288.2 FedEx Cup points Lee would be upgraded to the major extension category, meaning he would secure fully exempt status for the remainder of the season.
Today's result secures 245 of those points and Lee now has three tournaments to lodge the remainder, the first coming at the World Wide Technology Championship in Mexico.
"Next week is Cancun, which I've done very well at a lot of years, so I'm looking forward to playing in that next week," Lee said.
Lee's sole PGA Tour victory came at the Greenbrier Classic six years ago when he defeated David Hearn, Kevin Kisner and Robert Streb in a playoff.