Is the chain routed properly through the derailleur? Often times there is a tab between the jockey wheels. The chain may be on the wrong side of the tab.

If the hanger is cracked, I'd check that.

Also what is the capacity of your system? (front ring-front ring)+(big cog-small cog)=x
For example (50-34)+(32-11)=37 tooth capacity.
(50-34)=16, (32-11)=21 (16)+(21)=37
If your derailleur doesn't have 37 capacity in this example you are setting yourself up for problems.
Big/big puts too much pressure on derailleur springs and hanger. Or, conversly if adjusted so not to self-destruct in big/big, then small/small wouldn't take up slack.

Shimano is known for being conservative in their ratings, but it's probably not a good idea to disregard them completly.

How's the b-screw adjustment? Metal shavings from driving derailleur cage into side of gear, maybe?