feTile and feImage -- radical inconsistencies across browsers

I suspect that what I'm seeing here is just a bevy of browser bugs, rather
than underspecification in the spec, but bear with me.

 

http://granite.sru.edu/~ddailey/svg/feTile.svg 

 

If the IRI is local (as it is here) then Firefox (8) and Opera (12) seem to
give up. Both seem happy with an external image. Chrome does something
thoroughly bizarre, but interesting (note how the second star but not the
image is incorporated into the pattern). Safari (windows) doesn't do
anything. IE/ASV does rather what I'd hoped.

 

The trouble doesn't seem to go away if the local image in feImage is not
transformed though the browsers present yet another set of curiosities.

 

The overall question I was trying to ask was "does feTile really add
anything that <pattern> doesn't? And does <feImage> really do anything that
<image> doesn't?" I'm relatively certain that the answer is yes, but it's
hard to convince myself in the absence of such oddities. Is ASV's behavior
the proper behavior here? I don't see anything in the testsuite at
http://www.w3.org/Graphics/SVG/Test/20110816/harness/htmlObjectApproved/inde
x.html that would address this issue. 

 

Incidentally, playing around with the filter's bounding box and primitive
units and the like didn't seem to make a difference.

 

Cheers

David