That would be in my opinion be a propstrike and as such the engine would need to be pulled for inspection....... Lycoming have indeed altered the definition of prop strikes to include taxying through long grass, water or anything that causes a drop in RPM...indeed knocking the prop with the likes of a hangar door is now also counted as a strike....... the bolt on the back end of the crank would also require replacement as these have been known to fail on a couple of occasions in the US with the loss of life... when it goes you lose drive to the mags, fuel pump if fitted, oil pump and the camshaft...
BUT be careful what you say against a person on a public forum ok as this may come back to haunt you
see
http://www.lycoming.com/support/publ...dfs/SB533A.pdf
http://www.lycoming.com/support/publ...dfs/SB475C.pdf