hi, yep martin west discusses the same line and others and gives the same explanation, in "a new companion to homer" chapter 9 pg 229. i've scanned the relevant page for you, which has other e.g.s too:
http://www.freewebs.com/mhninaeide/WestSonantR.pdf
i've also discussed other homeric scansion irregularities in the intro to my scansion of iliad b here:
http://www.freewebs.com/mhninaeide/Ilia ... xt2006.pdf
cheers, chad.