Hypothetically, there could totally be an Aberrant with neutral or positive effects. Which means that, statistically, it’s almost certainly happened at some point. Why people don’t know about them, I’ll leave up to your deduction.
From my notes, there exists a low-powered, Scourge-type Aberrant that provides the perfect cup of coffee, which is immediately and forever addicting, but doesn’t force you to drink it or anything.
There are two problem with trying to find a harmless Aberrant. First, magic has a cost, and while Aberrants don’t have the same limitations as mortal sorcerers, that concept often still gets built in to their anomalous effect. Secondly, a break event is a horrible, traumatic event born of turmoil, pain, and desperation. It’s impossible for the person breaking to miss that fact.