1Password 5 and 6 also use the bundle ID com.agilebits.onepassword4.
Basically, what is happening is that Keyboard Maestro is activating 1Password, but then it cannot get the process for 1Password (pid 2657).
You could run the Terminal command:
ps axuwww | grep 1Password
to see if there are multiple entires or something else odd going on.
Otherwise, the issue is simply that the system is not returning the right information (which sadly, for anything related to NSRunningApplications is entirely likely).
Restarting your Mac may clear it up.
A sledgehammer workaround is to simply set the action to have a short timeout and no reporting of issues.