Can you try something for me... can you try installing the Mycelium wallet app: https://play.google.com/store/apps/details?id=com.mycelium.wallet and then restoring the seed in that application and check to see what transactions you can see?

I've just restored an old Mycelium seed into Coinbase... and it's missing the first couple of transactions from the wallet history. So, it seems that perhaps the Coinbase app might be "broken"?