Kevin Lee has been displaying rubber-leg tendencies throughout his UFC career. Even when he was dominant against a beaten up Barboza, Lee was still caught with a shot that made him do the chicken dance.
On top of that, Lee is very insecure, reckless, has difficulty managing his gas tank which leads to sloppy technique. He lost a fight he was dominating against Tony Ferguson. It was an easy fight for Kevin Lee to win, but he got reckless. Lee could have easily 5-0 Tony Ferguson by simply securing the TD and faking GnP. Instead, he got himself triangled.
Even in his fight against Gillespie, Lee didn't show that he had improved his fight IQ. He is a tremendous talent with a suspect chin, and under-developed fight IQ (no attention to details).
I will never bet on Kevin Lee, because I have seen him lose when he was dominant and in a lot of control. He doesn't pay attention to details, and he is often liable to "get caught."