Sorry to hear about the bug. It would be weird if just casting the spell caused it, though. Were you only using Fire? What happens if you switch to a different spell, then back to Fire?
Unless it all happened during a single fight, the issue could have been with a different button as well - I tested it and the passage transitions are fast enough so that if you spam click, you can click another button that appears on a new screen without even seeing it.
If this is indeed some weird Twine issue, with the engine breaking down if you spam click too fast, I'm afraid I can't do anything about it, but if the problem is somewhere in the code, I'll try to find it and fix it.