Yikes, sorry about that. 🙁 It's a different cause than before, with similar effect. I'm afraid I rushed moving the dopesheet timeline last night and didn't realize I broke something. I didn't see it because the particular project I used to test had an animation whose starting pose was the same as the setup pose. Anyway, I'm uploading 1.6.24 now with a fix. Sorry!
Edit: it's available now.
In case you need to restore an older version of your project, any time you save a project, Spine saves a copy in your user directory:
Windows: <user home folder>\Spine\backup\
Mac: <user home folder>/Library/Application Support/Spine/backup/
Linux: <user home folder>/.spine/backup/