Is Darkhawk Attack Synergy Bugged?

Hello,
Darkhawk attack synergy (friends synergy) says that "All champions gain +5% attack", but it increases attack of synergy members only, not all champions. Is there a bug or is this normal?

Darkhawk attack synergy (friends synergy) says that "All champions gain +5% attack", but it increases attack of synergy members only, not all champions. Is there a bug or is this normal?

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I also realised that both of Lv2 and Lv3 Friends synergy have +5% attack rating, not like Nemesis synergy which is +5% for Lv2 and +6% for Lv3.
I am sorry, I know I should not tag your name, but I can not get an answer. Could you help? thank you.