Here is what I did
1. drag 2 items onto the timeline
2. drag a Linear Wipe onto item 1
3. ctrl+c (this copies the effect at it's current state?)
4. change some properties.
5. click on item 2
6. ctrl-v (and all the changed properties is carried over)
The problem is, the pasted Effect contains changes made AFTER I press ctrl-C, so each time I have to deleted all the copied over properties.
Is this a feature or a bug in CS5?
It would have to be a bug. I've never, ever encountered anything like that before. I'd say that it's impossible (at least from a logical standpoint), so I can't imagine what's happening. I cannot replicate this.
Strike that, reverse it. I just replicated this... very weird. A bug, without a doubt: Adobe - Feature Request/Bug Report Form
For what it's worth, this also affects:
Actually... this affects EVERY effect! This must be something lower level than just a particular type of effect, then. Weird.