FYI updated to latest RC last night [Version 0.99.126.4.1.11-rc (WebKit 619.1.1)] and still have the not loading/refreshing issue under Catalina.
One thing i notice is that the Google results page works (or not) slightly differently under Orion with the old content blocker database loaded versus the latest. I hadn't been updating the Content Blocker database with each Orion update so by default my RC browsers are back at 1/1/24 7:00pm. With one of the latest RC but not updating the Content Blocker database, the hover over started working again such that for example when I hover over a link from Google results, it underlines. When I updated the Content blocker database after an RC update, the hover over broke. This hover-over behavior is not important to me but rather mentioning in case a clue to the issue. Happy to try alternate experiments around this if helpful. Or if not clear yet what I am talking about will post a video.
FYI I have tried all these tests with Compatibility Mode enabled (or not) and it doesn't make a difference in this issue.