Neat Video & Neat Image community

I am having a lot of trouble with the applied NV effect disappearing from clips in my timeline once rendered. I have tried un-checking and re-checking the effect, as well as removing and reapplying the filter and still get the same result. Prior to rendering, the effect appears fine, then goes away as soon as rendering is complete. The problem is somewhat intermittent, as two of the short clips in the timeline retain the effect after render, but the majority do not, no matter what or how many times I have tried.
I have been working on several projects with the same settings, and there have been a few occasions where this has occurred, but has usually been remedied by un-checking and re-checking the filter, or reapplying.
I am working with HDV in a pro res 422 sequence, FCP7, on a macbook pro.
Thanks for any advice you can offer!!

Do you mean the instance of effect disappearing from the list of effects applied to a specific clip or the actual noise reduction disappearing in FCP preview (so that image looks noisy again)?

Can you reproduce this in a test project with just one clip?

Thank you,
Vlad