I had the same issue, on over 500 poses, so fix them manually was a no go for me
I did instead a quick blueprint batch to do the job automatically, I past it here in case someone else need it
The main hint here is that the broken poses has an associated animation, sharing the same name with just a different post-fix: _pose for poses and _anim for animation source
So, here the blueprint
It is an AssetActionUtility, called by right clicking on all the poses assets → Scripted asset action
Hope it helps