Stable update: New Linux & Steam Deck exporter; Steam and File System improvements & loads more.
This is confirmed after rolling back to version R407.2. Sticking with that version for now. Sad because I wasted 2 hrs trying to understand what the problem was :/. Other than that this release looks promising but I really wished that all the new changes were listed instead of "Lots of improvements for Flowcharts including 'Preset' nodes, support for multiple tags, a new empty flowchart view, and more". There should be a comprehensive list of changes to each change, especially if it is going to break things.
There is a comprehensive list of changes in the beta releases in all intervening releases - they're all linked at the start of the release notes. I don't believe anyone reported any such issues during the beta period - if you can please do file an issue about any new problems and if they are regressions since the previous stable release they will be prioritized.