Question concerning "double baking".

Upfront I am NOT a baker but I had an incident happen a few days about that has me scratching my head. Last week when my Android phone was crashing (and despite the Magma wallet holding steady) I thought it would be prudent to move my coins from my Magma wallet to my Coinbase vault. Fast forward a couple of days, I get a new phone, reload my Magma wallet and move my coins from Coinbase back to my phone. I noticed that I didn't lose any of my (future) rewards from my current baker AND I accumulated a cycles worth of rewards from Coinbase. How does that work? Were my delegated coins "double baked" or was there some sloppy bookkeeping from my baker or Coinbase?