Undo/Redo are completely broken for me on Resolve 17.2.2 (Windows x64) as well, on both the Edit and Color page. Sometimes it works completely fine (including multiple Undos/Redos). Often I can Undo only a single step on the Color Page, and cannot redo it. And sometimes neither do anything.
Usually when it breaks, the undo steps are listed in the history, but grayed out. I don't know why they're grayed out. And usually once Undo doesn't work (or only with one step), it stays like that until you reload Resolve.
Example: I just deleted a bunch of clips & timelines in the media pool, and accidentally a clip I need. Undo worked for a single step, but the deletions happened over several steps. They are all listed in the Undo history, this time with nothing grayed out, but I still can't go back more than the first deletion step. I can click earlier steps in UI, but nothing happens:
- history.jpg (104.53 KiB) Viewed 7398 times
Live save isn't a workaround, because it is always saving every change, so 9/10 times, when you 'Revert to last saved version' it already saved what you just accidentally did! I've lost a few things that way that took time to rebuild, and/or I have to find & load a project backup (and hope it isn't too old).
This is a horrible experience.
EDIT: it would be much more useful if 'Revert to last saved version' reverted to the last _manually_ saved version, rather than the live saved version (if live save is enabled). Otherwise you're usually not reverting any changes.