The earth is neither a perfect sphere nor is gravity uniform over the earth’s surface. The ground is also moving around, naturally due to plate tectonics but also due to human factors like oil and gas extraction as well as the depleting of fossil water. There might be more factors at play, but these alone are probably enough variation to explain this difference.
In their defense the previous government was a puppet government installed and propped up by the US. It wasn’t particularly popular and could never sustain itself without direct foreign military support.