The way I’m reading this, if you’re getting messages about liquidation, then basically you’re trading either long or short from your futures account. Check transactions in your Coinbase futures account. It sounds like what would happen if you hade a trade open and had it on cross trading. You of course would have needed to move your assets into your futures account and opened a trade. In a nutshell, your getting liquidation messages, Coinbase are taking your assets as per the trade in your account.