ConwayLife.com

In the iOS version of Golly, if you pause the simulation, start drawing cells, and then unpause it without taking your finger off the screen, you'll continue drawing cells while the simulation is running. This doesn't cause any problems at first, but if you try to move your finger quickly enough, it'll crash with the error "Illegal operation while calculating."

This really is relatively minor, and honestly, likely the only way you're going to run into it is if you actually try to do it. Still, I thought it should be mentioned.

Yep, I can confirm the bug. Only seems to happen in HashLife and the other hash-based algorithms -- couldn't get the bug to occur in QuickLife.

Thanks for reporting it. I'll have a look at fixing it the next time I work on the iOS version of Golly (not likely to be any time soon -- Apple make it ridiculously complicated to release new versions on their app store).