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A weird bug after the CP update
The max CP of a weedle is 397, but 392 for its evolution form, kakuna.
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Kakuna Att: 46 Def 80 Stam 90
Weedle 63 Def 55 Stam 80
So it's evolved form does have more stats. (216 total for Kakuna 198 for Weedle) but because Attack is weighted heavier in CP formula, Weedles 17 attack is worth more than 25 Def 10 Stam.
You see this kind of thing a lot when you check IVs.
You can have a pokemon with say 600 CP and 40/45 IVs and then another with say 590 and get 42/45 just because the first pokemon has "Blown Away 15 attack" and the second one only has 12 attack.