I agree with you, but I’ve already “solved” the problem. Just check if fully levelling and traiting a troop will get you an increase in kingdom power level before you level and trait it.
Peryton wouldn’t have raised Dragon’s Claw’s power level from 7 to 8 for me if I fully levelled and traited it, so I just gave it all the traits but left it at level 1.
Now I can field a defense with powerscore 6740 if I want to.