Are they really strokes in the original? ID shouldn't be converting to shapes randomly. Are both documents in CS5.5?
as far as the effects, that probably means you accidentally set them with nothing selected and they are now defaults for all new objects.
Although as I re-read the description it seems the effects are not added until you try to edit, so it probably is not what I just said. This is just odd enough that it might be worth trying a prefs replacement. see Replace Your Preferences
Yes, these are just two horizontal lines. The lengths are different, the strokes are black but different sizes on each. When I paste them, they paste as horizontal lines, but are filled white, with no stroke. As soon as I change the stroke color from none to black, the effects are applied.
After some more tinkering, it may just be the document I was pasting into. When I create a new document, the lines paste as they were copied. One odd thing though, a vertical line I was pasting with the other horizontal lines always pasted fine, just as it was copied. Weird.
I'll try the pref replacement. Thanks for the tip!
if it works ok in a new file it probably isn't the prefs.