Strange characters appeared while writing a message on iOS

I was writing a message on AirBnB(iOS app) and quickly pressed the thumbs up(at least I think) and smiley face(U+1F60A) emoji But instead got this output on the text box: Looks like letter 'A' in a black and white square(+reversed variation). Interestingly it wasn't possible to copy these characters, that is it was, but on paste action, nothing was pasted... I'm really curious what could have caused this, I presume, Unicode letter. At least I would like to know what exact Unicode characters are these(code)? Are emojis constructed of 2 Unicode chars so I somehow managed to glitch one emoji inside another and thus made it deconstruct to these individual chars?!