I have this strange thing that like only half of my turrets actually updated to the upgraded ones. That's weird.

Can you please provide me with the save and any information about what you did to cause the bug. For example did you build the turrets by hand or with robots, after or before research?

I had a similar problem. Before the upgrade my turrets were fine, but after it took effect almost none of them would actually fire or do damage. This happened to ones that were already placed down. I tried placing a new one myself but it still had the same problem. I hadn't checked if robots caused the issue as well, but I suspect they might.