Cannot disable "Flight=true" in server.properties, and minehut panel has no affect

[Bonneville]

When attempting to disable "Allow-Flight=true" to "Allow-Flight=false" in server.properties, upon starting the server it automatically resets to "Allow-Flight=true".  Changing the minehut control panel seems useless and has zero changes. This is causing players to fly and generate large amounts of chunks, as well as lag the server. How would I disable flight? It is just the default kick I want.