According to Mike this isn’t a bug but posting here anyway as it feels jank.
If Storm Crow is your only minion, or just the first minion summoned it (namely the Fulminating Caw node) doesn’t get the benefit of Tempest Bond because (again according to Mike) Tempest Bond doesn’t actually take effect until after a minion is summoned. Summoning another minion doesn’t do anything to rectify the first, but summoning a temporary minion such as a totem and then summoning your storm crows will enable them to get the full benefit of Tempest Bond.