Yeah this issue is known, and I’m sure the devs are looking into it. Though I’ve never actually seen any response on if they are looking into the problem or not.
Here is another thread citing the same issues. I posted on that one with a similar issue, showing it doesn’t just have to be a warlock’s demonic pact.
http://community.gemsofwar.com/t/bug-with-ranger-spell-and-daemonic-pact/17545