Right off I noticed 2.7.0 is mining on my backup pools even though I'm using failover. Version 2.6.5 says pool 0 (my primary) is online and it stays on it. Version 2.7.0 seems to mine all the pools in my list in spite of my pool management strategy being failover.
Did you specify the --failover-only flag (or set that option some other way)? Default failover leaks work to backup pools and is supposed to.