I saw similar behavior when using history this afternoon. Running 2023.2. Unlike yourself, I didn’t reboot. I changed to a different page then changed back to the history page. Worked without an issue the second time around.
I’ll keep an eye on this behavior and report it as a problem if I see it occur again.
I have the exact same problem. Restarting HA didn’t help, rebooting the whole Intel NUC didn’t help. Switching to other pages and back didn’t help. I’m stuck and can’t use the history feature anymore.
Update: I found a workaround!
Although the little filter-with-an-X-icon in the top right corner seems to be inactive because greyed-out it actually is clickable! This removed the “wrong” entity selection and everything is back to normal now – phew! – Hope this works for you, too, @Thorn?!