Email message misinterpreted

I wrote to my friend the following, and cc'd Sandy:

Hey Cory,

This stupid power of attorney needs to be witnessed by two people. Can you remind me to have it signed on monday?

Sandy, can you remind me and Cory to sign the power of attorney form on Monday at 4:00?

Sandy recorded this as a reminder to 'get it signed' on Monday, didn't remind Cory, and didn't record the time.

I don't think this is how this is meant to work.