OK so this just happened to me. I have a Mozilla account since I was using their Monitor and VPN service. Last year I canceled those subscriptions because it wasn’t really working for me. Today I start up Firefox and I was signed in to my Mozilla account! I never signed in through Firefox. They’re sus now.
Because a program acting in an unexpected way is suspicious…
No it’s not, what you are describing is a bug. Your argument implies that any bug in a software should be considered suspicious behavior. Du you also think it’s sus if your iPhone camera glitches out?