Thanks for reporting this @johnbedo and @soodomaa
I have fixed it at my end. Will wait for 48hrs for other bug reports and fix all those and release a patch 2.8.1 soon.
As this issue is not a breaking issue, it can be on hold for at least 48hrs.
P.S Even if the page crashes after cancelling the order, the order is canceled on the server.
A reload of the page solves the issue temporarily.
Cause: Implemented the Lazy Loading of orders in 2.8.0 that cause a slight hiccup.