Mine has flared occasionally. I curse a lot when it happens. It usually is not a problem but if you shoot into strong light a lot, you may want to consider holding your hand between the light source and the viewfinder. In my experience that seem to take care of the worst of the problem and it is probably a lot less expensive than swapping viewfinders. It is a bit trickier to focus when you are using one hand to shield the viewfinder but true rangefinder fans are used to little set backs like this.