Strange BUG - Cant go to next Age

A strange bug happened to me just now.

I was playing a TR 40min (as France) game when, upon arriving at AGE IV, I noticed that I couldn’t go to AGE V, because the button just wasn’t there.

I tried deleting the TownCenters but that didn’t work either. I deleted them all and couldn’t build anything anymore because it was a treaty.

I was cursed by the other player and I was confused.

Has it ever happened to any of you to get bugged without being able to go to the next age?

Maybe you had set max age at IV

No, because my enemy could go to AGE V, i and was not the host anyway.