ah-Hah! The common denominator, Win 11. I run two machines that I access the Fool on, a Dell/Intel (i5-7400) and an older HP/AMD (A10-5700) , both with Win 10. Don’t have any issues with the Fool.
Consider the flipside of the issue: maybe your OS and browsers have received an update, but the Fool has not updated it’s site to work with the latest browser updates.
Steve