I’m not the dev, and I haven’t tried the 4.19 preview yet, so I can’t confirm if the bug was fixed.
But there is a way to clean up states that are not working, regardless of version. Copy everything that is in that pasted state, then delete the state. Make a new state through the right-click menu and give it the same name. Then paste the nodes back into the new state.
You will have to redo all the transitions, events, and blends still, but at least the state will have been copied and now all the nodes should be fixed. If you are still running into issues, it’s possible that there are other bugs occurring for you, that are separate from this one.
Good luck!