Exactly, the Predators at the beginning of Incursion were hunters expecting to hunt small game (independent security guards/mercenaries aka "Indies"), the CM were called in and that's how they were able to take them down. The CM still lost two marines.
The Predators on UMF-12 were ambushed and unprepared. It was literally a settlement that got overrun by Xenomorphs, and the ships that the marines took out were unprepared and probably panicked average non-war ships leaving to regroup and get back to their senses before planning a counterattack. And still one of them destroyed the marine ship with a burst of lasers.
Then we have Predators who are ready to kick ass. Hashori was dominating Xenomorphs, the Preds on the Zeere-Za put up quite a fight before its destruction due to an ambush by multiple Rage ships. Hashori also singlehandedly fought a space battle on her own against the same pursuing Rage ships without Liliya even realizing lol.
And during a Rage attack, the Marines were getting their asses kicked until the Predators joined in and destroyed the Rage ship. Plus during one bit inside a Rage ship, it was the Predators who
Spoiler
captured the enemy Android and handed it to the humans (completely mangled and f**ked up) before leaving. They took out several Xenomorphs as well.
Unprepared, anything will get its ass kicked no matter what.
It's when they are prepared, that the Predators show their true potential in combat. That's how it's always been with them when you think of it, in the films and such, they were always prepared and dominating the chess board. It is only when they are unprepared for a surprise that they get truly screwed such as in this book.