To localize the problem to the switch (My guess) you could try removing the tailcap and taping a piece of foil to the exposed rear of the light, connecting the battery to the body. Use the light like this for awhile, and if it doesn't flicker, bingo: it's likely the switch.
I've had an experience with Inova's 'top quality', my T3 has a couple pits and noticeable debris on the optic. Not what I expected. Customer service said I could return it to the place of purchase (not possible; online) or send it off to them... The latter option would leave me without my beloved, though flawed, flashlight for MONTHS. Ohwell
-Crow