I replaced my MWF Smart Filter with a cheaper replacement and I noticed it had an "O" ring laying in the center of the filter. When I removed the GE filter, there was no "O" ring in the same center section. Can I assume its stuck up above. I just installed the replacement with the ring in place.
The compatible replacement filters come with an O-ring for added protection from leaks. If there were no leaks when you installed the filter, then you should not have any issues.