It was sent from ibotta. Go back into it it should be on your screen somewhere maybe the scroll stuff on top click it and enter your email. If you really did get an invite you have to put your email in to get it just like last year. It starts 2/1/21
Virtually the same thing happened to me, I got an in app invite and before I could successfully interact with it, the app restarted and the invite was gone. I don't know what I missed out on, but would like the opportunity to find out.