I've noticed a theme with the past 50+ pup toys that no matter what kind of toy they are or what pup I give them to, they only give Luck. I just gave 13 pup toys to one pup all at once and each one gave Luck. Here's a gallery with the screenshots. https://postimg.cc/gallery/qhJpnLK

I don't believe this is a bug , pup toys give cp to 1 of 6 "randomly selected stats " but I've noticed that it gives it to the lowest stat first . So I believe luck was the lowest one so that got the pup toy cp

side note I want to say pup toys wouldn't add cp to stats that are filled to max ( pup toy bundles on the other hand will since it seems like each bundle gives to a specific stat I've noticed)

The wolf you're giving pup toys to can only get luck cp from pup toys because every other stat is full.

Pup toys can only give cp to luck, perception, stealth, battle, resolve and agility