Yay!
I assume Inflation is increased by having the Commerce -> Wealth % high for too long, but I guess it's inevitable for that to happen in your mod since Cottages are unlocked later.
Previously it was just based on the number of turns that have passed. K-Mod (merged in 1.24) made some changes that also linked it to tech progression and trading, but I wasn't aware of this. Seems to be something else affecting it too, but I'm not sure what. Decided to remove it, rather than untangling further.