I've been mass deleting/rebuying units several times in a long campaign. After the last mission I went to the core repair screen and had ~9000 repair points left. I went to "expand core" and my available points went from ~9000 to -55820 and then to several million as I tried unsuccesfuly to buy more helicopters. After leaving the "expand core" screen I can't go back again, and I can't repair any of my troops either.
Looks like my extremely high repair points overflowed into the negative. My force consists of about 55,000 points worth of helos, an HQ and nothing else.
Additionally, I converted my HQ to an SA 10 and its unit icon isn't showing up in-game. Not even the default WinSPMBT icon shows up in its place, just a blank hex.
The SA 10 is still able to fire for the first turn of the game after being retreated off-map in deployment.