Hi Ray, I can’t test in Opera ftm, but I think you’ve found an Opera bug again. 
I had the problem when I was testing for the “float center” quiz. Now I can’t remember if I ever compared how a self cleared box behaved in Opera vs other browsers. If in this case an e.g. overflow:hidden paragraph could overlap the float if the upper edge should pass over and touch the floatpusher. (I think Opera does not.)
Possibly this odd float wrap is not reported as a bug yet?
I couldn’t agree more. I ran into that wall a couple of times 
Yes, Opera bugs are vicious like an IE7 bug 
I’ve learned not to jump the gun and start calling them bugs to soon but I think your right. It looks like the bug is introduced by the identical line-height of the sandbag. What stumps me though is why it finally decides to wrap when width is reduced.
Here is the latest code I was testing with.
Here are some screenshots of the wrapping text at narrowed widths and lack of wrapping when space is available on the right of the cleared float.
No Text Wrap Above: http://www.css-lab.com/bug-test/nowrap-opera.jpg
Wrapping Text: http://www.css-lab.com/bug-test/wrap-opera.jpg
Strange behavior indeed 
