So, this has been an ongoing error since I've been playing, which is since before the insects came around.
The problem is, when I upgrade a building, I get workers coming back. But before I'll have some unemployment. After, I'll have MORE unemployment, despite having more available jobs. Before, the fire drill would fix it. But now, when I use the fire drill, none of my buildings are employed. I'm getting massive unemployment, and many of my buildings don't have a single worker. Some others only have one or two. But if I upgrade one, it fills with workers lightning fast. But I can't upgrade some of them, as they can't be upgraded.
I am using the most recent game version and I'm on an Android phone. Moto Z Play, phone and operating system up to date.