I've now sent 2 transactions from the Monero GUI to an online wallet over 2 weeks apart, none of the amounts have posted on the online wallet and on both transaction in the 'History' tab both have "Unknown recipient" in the transaction list entry 'To:' field.
It took me a little bit of troubleshooting to notice this.
I entered the other wallet's address on both times, this time I know for sure as I just did it. I checked out this guide (https://www.getmonero.org/resources/user-guides/prove-payment.html) and it shows the 'To:' field has the receiving address.
Is my install of the Monero GUI hacked? I downloaded it directly from getmonero.org so I thought it's good.
I am running it in Advanced mode using a remote node/host, and wallet and daemon are fully synchronized.