BullGuard doesn't use a plugin. The engine controls the browser directly.
The search ticks are indeed not displayed sometimes, in particular when Google updates the browser, Howeveer, even if the green checkmarks are not displayed, when attempting to reach a malicious website, your access will still be blocked by the engine, so you are still perfectly safe. This should be fixed automatically in an update, so there is no action to take on your part.
I apologize for the inconvenience.