light shift during transitions?

hey all
so i inherited a project with a bunch of rotating box transitions. during the transition the scenes are noticeably darker, and as soon as the transition ends there is a significant light shift back to normal. everything is rendered.
i can fix the problem by keyframing brightness, but i am wondering why the the shift is there in the first place. anyone have any ideas? anything i can do to prevent it?
thanks!
also, i keyframed my brightness levels, then tried to "paste attributes" paste my filters onto other clips. the filter was successfully pasted, but not the keyframes. any ideas?
thanks again everyone!
greg

Are you sure it's fully rendered? I saw something like this in a 10bit uncompressed show where the fades and dissolves would have brightness bumps. If I remember correctly, it turned out that the effects were in fact rendered proxies and that I had to force FCP to fully render everything, at which point the transitions behaved properly.

yeah, tom, that was my original thought. so i went up to the "render selection" and made sure "full" was selected. i did that despite the blue/grey bar which i am pretty sure means it is fully rendered. also, the sequences could be exported, which to me means they have been rendered. right?
or am i missing some other way to make it render more fully?
thanks!

Could also be corrupt render files. Dump your render files using Render Manager (under Tools) and re-render.

derek
thanks for the suggestion. just dumped the render files and re-rendered to no avail.

Okay, try this -- delete the transition (if it's not a default FCP transition, drag it into the Browser to preserve it), select the clips around the transition, press SHIFT-D to take them offline (choose "Leave media on disk", don't choose "Move to Trash" or "Delete from Disk". Now go to File - Reconnect Media to reconnect the clips. Reapply the transition and render.

derek
no go. the weird part is that when the transition has not been rendered and i go frame-by-frame through it, there is no light shift. then i render it and the damn shift reappears.
it was shot on betacam and is stored on an external firewire800. any chance that it is a data throughput issue? 2 streams of betacam over firewire800 = degradation? i'm grasping at straws here.
thanks!!
greg

any chance that there is a genarts saphire effect or transition applied to any of the clips? ive seen this exact thing happen with several of those.

or if there is any difference in the format of the two clps. like field dominance, frame rate, codec, aspect ratio etc... ive seen that happen before as well

Sequence Settings>Video Processing

See if the text on the right "Codecs which...material" applies to the codec you are currently using.