Interesting observation ... I usually don't have the status "flip flopping" very often. Yes, when a bunch of cities change state, it does take a while.
WLTKD - We Love the King Day - (or Queen or President or whatever): is determined by the net happiness of a city. I build lots of roads, trying to ensure that all cities are connected to all the luxuries.
- If someone declares war on me, ending my import of a luxury, then I might drop out of WLTKD in a lot of cities
- A trade deal ends / expires, I lose a luxury, might cause me to drop out of WLTKD
- If my war has been dragging on for 18-20 turns, and I have not bumped up the lux slider, then war weariness might drop me out of WLKTD in a lot of cities
- When I end that war, especially if I have bumped up the lux slider, I might find myself gaining WLTKD in many cities. The war weariness disappears.
But those events are usually separated by a bunch of turns. Yes, I get a wave of popups when they happen, but I don't get another wave until many turns later. In the late game, I usually have nearly all the luxuries identified, imported, or conquered and so my happiness situation is fairly stable.
I don't know a way of turning off the popup. What things are happening in your games where the popups come in waves?