When they've been spending the last several months supposedly polishing and bug fixing, it's insane that the latest update is, "Oh the ending wasn't epic enough so we're going to go back and rework the content". This means the cycle of polishing and bug fixing is reset, probably tacking several months more onto the release date. If the progress tracker was even remotely accurate, it would be moving backwards based on that last update.
But it moved backwards. Those new tasks got added to the "Edit" bar once the initially planned content was done and they could properly test it and feel that this final part was just not working. This is the last progress tracker from the 'creation' phase:
And this was the next one, 5 days later. As you can see, the edit bar went up from 507 total tasks to 556, and these 50 new tasks include that last scene they weren't happy with.
And it's still going 'backwards' if you want to think about it that way, as now there are 565 edit tasks planned, and probably even some more will still be added before the release. But there has been an actual net progress of 33 edit tasks completed in this last month (42 actually done minus 9 new tasks added). Again, everything matches dev's words, as he claimed they'd want to focus on those edits in May and then, in June, he would focus on "bugs", hoping for the whole thing to be ready for external testers and then released by the end of June - if they're happy enough with the result.