You definitely didn't receive a 5* Cad Bane since the datacards only provide 4* (at best).
You received a 3* Cad Bane, which converted to 25 shards.
A 4* would have converted to 32 Shards.
[A 5* would have been 40.]
Personally, I'd be happy with 25 shards for Cad, it beats 7 for Ugnaught or something.
When you receive a card or shards it shows the number needed like 25/65 to get to the next star leve but shows your character as the next star level up. It is deceiving because it's opposite of how they appear in the character inventory.
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You received a 3* Cad Bane, which converted to 25 shards.
A 4* would have converted to 32 Shards.
[A 5* would have been 40.]
Personally, I'd be happy with 25 shards for Cad, it beats 7 for Ugnaught or something.