forum.freeciv.org

Like I said, Luxuries are locked. Shouldn't have anything to do with revolt.

My explanation would've been Citizen Governors having to switch workers to fulfill their gold requirements, but those aren't a thing in Freeciv-web yet.

The only other explanation I could think of is that there are some corner cases where the trade can't be divvied up evenly and the higher science rate would result in the last point going to science when otherwise it would have gone to luxury, causing disorder.

Yeah, in the end, it turns out it is (probably) some rounding effect because some cities end up in disorder.