When you have a mine near your houses, the houses sometime jo-jo with desirability, seen this in several cities, I cannot find a rational why it happens.
Because mines have negative desirability? Just like most industrial building, the rationale is self explanatory - would you like to live next to a mine?
When placing a mine, the default overlay is minerals, so you can’t see this affect straight away. Press ‘G’ while building a mine and you’ll see the large red radius.
This has nothing to do with my report at all, you can see the negative impact of the mine on the desirability listing of the house in question, only the fact that the house upgrades itself and then later digresses with the exact same total, without any change on the map, does not sound very logical.
Could it be that the amount of ore you were mining reached the storage cap you had set, causing the mine to go idle?
When the mine is idle, the negative effect on nearby residences disappears, so some of them may have upgraded to Tier 4 during that time.
Are you trying to say that the mine’s desirability sometimes disappears? [on second reading, I’m guessing jo-jo is meant to be yo-yo?] Show us a screenshot of that too, so we can see what’s happening. As @Hota said, it’s likely because the mine is sometimes switched off: either manually or when a production cap is hit.
Ah, I had no idea it was differnt in English.
It could be that if the mine closes the house upgrades, good point, let me find out.
Most likely, your mines were paused by production limits, which removed their penalty from the area and allowed the homes to upgrade. Then production resumed.