Not sure if this is a bug or just a game mechanic I was not expecting?

Setup a game with large map, humankind difficultly and all other config's set to be randomly selected.

At turn 126 my empire (purple) controlled significantly more territories than all my neighbors including the fame leading "green" empire.

On turn 126 the vast majority of land above my empire (purple) was unsettled with scattered independent people:

Influence at start of turn 126 was also very limited in the unsettled areas:

In just one turn, at start of turn 127 everything flipped and green suddenly controlled nearly every unclaimed territory and independent city across the length of the entire map:

I was investing gold into the independent cites of Paracas and Parthians reaching 22 influence points in each and was leader in influence by 19 points over green at the start of turn:

Yet the influence map shows green with 100% control over these independent cities and many others where they were not a local influence leader:

Green had a solid fame lead at this point in the game so maybe they crossed some threshold where the whole world map flips in their favor?

In retrospect, this probably should have been posted on the general comments forum as opposed to bug reports forum but I don't want to retype all this ;)

Khmer Turn 126 Before Influence.ctr

Khmer Turn 127 After Influence.ctr

Edit: grammar