Foolish mistake - ideas please?

Today I lost an amount of BTC transferring from Coinbase to my Coinbase wallet on iOS, all on the same device.

I logged onto Coinbase, my clipboard within the app still had the address for my wallet on it. It’s the last and only other place I have ever sent BTC, and I recognised the first four characters. So, without checking, I pasted it in and sent it. It wasn’t my wallet. So the money’s lost. My lazy bad.

Question is though, how did another address get onto the clipboard of my Coinbase app, when I’ve literally only ever used it to send to my own wallet, and no other transaction addresses have ever been entered by me. Is this malware on my iPhone?

I’ve googled this and seen scams for desktop computers, but no results for iOS. I’d appreciate any insight anyone might have.