I think it is very hard to tell much from this picture. The part it covered in chips and fluid. The part is partially out of focus and light blasted in some areas. Though many people seem to be able to see things in photographs that I can't.
The photo does show that instead of cutting the metal, the tool tore out a chunk. I suppose that a broken tool could do that, but it seems more likely that tearing the chunk out broke the tool. Possibly there was an accumulation of material on the edge - changing the geometry to something like negative rake - or you hit an inclusion or void. Anyways, 'sticky' seems like the most apt description of this material. It could be work / strain hardening too. That process generates 'pockets' or 'bubbles' in the metal that cause all of these symptoms - chatter, sticky, and radical differences in hardness.
As an aside, I did a heat treatment yesterday. I live in the city (Toronto) so fire is mostly prohibited. I'm sure if they could figure out how to ban it outright, they would - but it turns out that it's just so darn useful for things like heat, hot water and cooking, that somehow it is still allowed. So I rigged up a barbeque with map gas and got some 1/4" ball bearings to glow red. Today I machined the softened balls into a Christmas present for the wife - and who says I leave things to the last minute. I planned 1 day in advance!