Prop Feathers and Engine Shuts down after landing????????

Today I was flying my Twin Comanche PA30 everything was great until after
landing. Once I had the wheels on the ground I pulled the power back to idle,
about three seconds or so after I pulled the power back the prop feathered and
the engine shut down. I let the engine cool down for about 30 min then started
the engine right up. Everything was running great. So I took off and flew
around for a while then came back to land, this time after I landed I put
the power back up to 1500 rpm, the oil temp was right below redline the oil
was at 50psi then the prop feathered and the engine shut down again. This also
happened to me yesterday. Every time I land the prop feathers and the engine
shuts down . Everythings always great until after landing. I only have 40
hours on the engine. Could anyone please help me out? Has this ever happened
to anyone before? Does anyone have any ideas on what it could be thanks for
everyone’s help.