Color changes between CS2 and CS4 opacity with effects turned on

Question

Howdie.
I don't run into issues much with Photoshop, and this one has me stumped.
I needed to drop back to CS2 in order to use a warp mesh plugin.  I saved out a small portion of a file that I created in CS4 (Only containing the layer I needed to warp) and then opened that file in CS2, turned off all the effects (drop shadow, inner glow, bevel & emboss), and applied the mesh warp, then saved the file.  I went back into CS4 and re-opened it there and copied its layers into the bigger, original file.  What is strange is that the colors were a LOT lighter than they should be when compared to the original unwarped layer.  So in an attempt to figure out what was wrong, I checked all of my layer opacities, filter settings, layer mixing mode, etc. and everything was exactly the same.  I even tried deleting the layer style and copying the layer style from the original layer...no change.  I turn off the effects and check the color of the object and it reads the same as the original layer.  Both layers have no semi-transparency in the colors.  I turn the effects on and it is all whacked out.  After a while, I figured out that the problem was that the layer opacity in the effects, although reading the same between both layers (70%), is behaving as if it should be at 90% opacity in the new layer in order to match the original.  Its as if the layer worked on in CS2 has brought with it some corrupted info in its definition, that never leaves and affects any Effects you try to apply to it.
Has anyone experienced this one before?

Answer 1

A liitle bit more info here.  Apparently, the pixel data for the warped parts screws with the effect, Inner Glow, in the Choke and Size sliders.  The sliders simply quit functioning and have an abrupt light/dark toggle effect roughly near about value "7".
The only way I could fix the problem was to do this convoluted solution, since Duplicate Layer does not work.
    1.  Clear the effects on the problem layer.
    2.  At this point you can either work on the problem layer directly or duplicate it to create a work layer.  Doesn't really matter because both layers will get deleted later anyway. 
    3.  With Channel Mixer, and for EACH color channel CMYK, move all 4 sliders hard left, so that the result is 0/0/0/0 for the CMYK values  (Do NOT use Brightness & Contrast in place of Channel Mixer because you will lose any blurred edges.  Also, using Channel Mixer does not swell or choke off the pixels along any "floating" shapes' edges). 
    4.  With the selection tool, create two small selection boxs at two opposite corners of the entire layer.  Fill them with any color. 
    5.  Select the entire layer (CNTL + A on a PC), and copy it to the clipboard. 
    6.  Create a new Alpha channel and Paste.  The little boxs at the opposite corners of the file were needed to precisely position a copy of the layer when we Paste it into the new channel.  The contents of the channel must be exactly registered with where the original shapes were in the problem layer. 
    7.  If you want, you can now delete the boxs in the corners of the channel by filling them with black. 
    8.  Create a new layer and load the selection (the channel) we just created. 
    9.  Fill it with the desired color. 
    10.  Copy the desired effects from the original layer before warping was done and to the new layer we just created. 
    11.  Delete the old problem layer. 
    12.  Done.