By chance do u have a link to the test of the refresh rate?
"Show refresh rate" option in developer options doesn't show less than 48Hz. We do agree it has to be updated to show correct as current implementation is defaulted to googles implementation.
Please update Samsung members app to latest version from galaxy store and send us an error report immediately after experiencing the issue from the Samsung member’s app -> Beta Feedback -> Error Reports to help us debug the issue. We apologize for the inconvenience and appreciate your contribution to the beta program.
One UI Beta Team
I did send the error report though, thanks (: