/anything.html problem since update to 2.4.2

Hi,
We updated to 2.4.2 on the 10th, and since the update are having an issue with redirects in this form

https://snhp.gsu.edu/somethingunique.html

They go directly to the ugly 404 page, not even our wordpress 404 page.

https://snhp.gsu.edu/somethingunique

Oddly enough, redirects in this form are working fine

https://snhp.gsu.edu/something/something.html

Our other redirects also appear fine. Any ideas on how we can fix this?

Thanks!
Dan

https://www.ads-software.com/plugins/redirection/