XrayArtist

I was a commercial photographer for 55 years and have seen some pretty large bubbles in view camera lenses. I’ve owned several that the bubbles were quite visible but even those there was absolutely no impact on images  
As to used value, knowing what the photo world is like today, it may reduce the resale value. The thing to do is simply keep it. I own one and it’s a tremendous lens so just make some great images with it and forget about the bubble. 

Shot with the X-T1, XF23 f1.4, Godox 685 and Godox X1T trigger. Hand held and dragging the shutter. Exposures between 1/4 to 1/15

So the lenses are quietly talking behind our backs. I knew I heard some grumbling the last time I closed the camera bag 😃