I suspect that "Buy-something hackers subscription: (unnamed)You do not receive emails from this subscription." is in the "Subscriptions to Payment service" section. It's a structural subscription which you have muted.
"You receive emails about this bug because you are a member of the team Buy-something hackers, which is directly subscribed to it." is the reason you're getting email. It's a direct subscription, separate from the structural subscription that you've muted.
"You will receive an email when any change is made or a comment is added." for the structural subscription should be faded and italicised if the subscription is muted. Is it not?
I suspect that "Buy-something hackers subscription: (unnamed)You do not receive emails from this subscription." is in the "Subscriptions to Payment service" section. It's a structural subscription which you have muted.
"You receive emails about this bug because you are a member of the team Buy-something hackers, which is directly subscribed to it." is the reason you're getting email. It's a direct subscription, separate from the structural subscription that you've muted.
"You will receive an email when any change is made or a comment is added." for the structural subscription should be faded and italicised if the subscription is muted. Is it not?