Dumb question: Why I can play Gears 5 MP even when I'm not gold anymore?

My Game pass ultimate subscription expired last week, and since I’m grinding POP! I didn’t buy gold again.

Well, today I played for the medals to unlock Marcus and I played 1 event match and 1 Jingle Juvies from start until last wave (we lose) and I turn off my Xbox. I didn’t realize that I could play even without gold until hours later, when I was on the supermarket’s checkout.

I search if Gears 5 is on Free Xbox weekend or Free play days, but the only thing that I found was Gears 5 was on free play days from Dec 10th to Dec 13th.

Thanks

Does anyone else on the console have gold? If yes, you are piggy-backing off of that.

If not, I have no idea lol

Or if he was game-sharing with a friend.

No, I was the only one who had gold/GPU on my Xbox.

Also, I played Gears 5 thanks to GPU, and I bought a digital copy this year (on discount).