FCPX Effects not working since upgrade to Yosemite

I originally posted this is the general "FCPX and Yosemite" topic, but as that topic is pretty general, I'd like to address this to others that may have a solution to this issue.

Note that this problem is not specific to one 3'rd party effect maker, it appears to be quite general. For example: Levels and Curves from Nattress, and many Universe effects from Red Giant.

I tried a clean install of FCPX, but that did not help.

Have you contacted the third parties? Red Giant plugins almost always break with a new OS or major application revision.

Thanks! I have just sent a support request to Nattress, but as I am in a bit of a bind and cannot wait indefinitely, I am considering downgrading back to Mavericks (via my Time Machine backup).. Any other inputs on this problem? Any experience about how long till there's a fix or bypass?

Red Giant MB Looks and Universe seems to be okay on my setup. Had a spinning beachball when I opened MBL the first time from within FCPX after upgrading to Yosemite, but after a relaunch of FCPX everything seems fine.

I will add that I found that 3'rd party effects that just change the appearance (e.g. blur, etc.) appear to work fine for me. The effects that change levels or curves don't work..

My issue is resolved. FxFactory has released an update that I had missed. So my critical effects are working again.
Thanks to all!