Todays Daily Spell somehow locked up once during solving, so that it did not accept any input. After reloading it worked fine as expected though. I did not try to use any arcane magic to cheat, I swear!
Hmm, this is a new one, I definitely want to fix that. Are you on mobile? Click/tap to pick letters, or keyboard? Did you do anything other than enter letters, like open the How to Play pop-up in the midst of solving?
This was on Firefox. I used the keyboard and the freeze happened while navigating with the arrow keys. The cursor was about to jump over a blank space when it froze. It seemed to be stuck at 100% CPU usage and did not accept any keyboard input or mouse interaction after that.
Super useful details, thank you! I found it. (Infinite loop when using the arrow keys but there's no other square to move to.) It should be fixed now, thanks again for the report.